Biofilm Responsive Zwitterionic Antimicrobial Nanoparticles to Treat Cutaneous InfectionClick to copy article linkArticle link copied!
- Sybil Obuobi*Sybil Obuobi*Phone + 47 77660261; Email [email protected]Drug Transport and Delivery Research Group, Department of Pharmacy, UIT The Arctic University of Norway, Tromsø 9037, NorwayMore by Sybil Obuobi
- Anna Ngoc PhungAnna Ngoc PhungDrug Transport and Delivery Research Group, Department of Pharmacy, UIT The Arctic University of Norway, Tromsø 9037, NorwayMore by Anna Ngoc Phung
- Kjersti JulinKjersti JulinHost Microbe Interaction research group, Department of Medical Biology, UIT The Arctic University of Norway, Tromsø 9037, NorwayMore by Kjersti Julin
- Mona JohannessenMona JohannessenHost Microbe Interaction research group, Department of Medical Biology, UIT The Arctic University of Norway, Tromsø 9037, NorwayMore by Mona Johannessen
- Nataša Škalko-BasnetNataša Škalko-BasnetDrug Transport and Delivery Research Group, Department of Pharmacy, UIT The Arctic University of Norway, Tromsø 9037, NorwayMore by Nataša Škalko-Basnet
Abstract
To avert the poor bioavailability of antibiotics during S. aureus biofilm infections, a series of zwitterionic nanoparticles containing nucleic acid nanostructures were fabricated for the delivery of vancomycin. The nanoparticles were prepared with three main lipids: (i) neutral (soy phosphatidylcholine; P), (ii) positively charged ionizable (1,2-dioleyloxy-3-dimethylaminopropane; D), and (iii) anionic (1,2-dipalmitoyl-sn-glycero-3-phospho((ethyl-1′,2′,3′-triazole) triethylene glycolmannose; M) or (cholesteryl hemisuccinate; C) lipids. The ratio of the anionic lipid was tuned between 0 and 10 mol %, and its impact on surface charge, size, stability, toxicity, and biofilm sensitivity was evaluated. Under biofilm mimicking conditions, the enzyme degradability (via dynamic light scattering (DLS)), antitoxin (via DLS and spectrophotometry), and antibiotic release profile was assessed. Additionally, biofilm penetration, prevention (in vitro), and eradication (ex vivo) of the vancomycin loaded formulation was investigated. Compared with the unmodified nanoparticles which exhibited the smallest size (188 nm), all three surface modified formulations showed significantly larger sizes (i.e., 222–277 nm). Under simulations of biofilm pH conditions, the mannose modified nanoparticle (PDM 90/5/5) displayed ideal charge reversal from a neutral (+1.69 ± 1.83 mV) to a cationic surface potential (+17.18 ± 2.16 mV) to improve bacteria binding and biofilm penetration. In the presence of relevant bacterial enzymes, the carrier rapidly released the DNA nanoparticles to function as an antitoxin against α-hemolysin. Controlled release of vancomycin prevented biofilm attachment and significantly reduced early stage biofilm formations within 24 h. Enhanced biocompatibility and significant ex vivo potency of the PDM 90/5/5 formulation was also observed. Taken together, these results emphasize the benefit of these nanocarriers as potential therapies against biofilm infections and fills the gap for multifunctional nanocarriers that prevent biofilm infections.
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You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
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Attribution (BY): Credit must be given to the creator.
*Disclaimer
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License Summary*
You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
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Attribution (BY): Credit must be given to the creator.
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1. Introduction
Scheme 1
2. Experimental Section
2.1. Materials
2.2. Bacterial Strains and Mammalian Cells
2.3. Preparation of Zwitterionic Nanoparticles
formulation | P(mol %) | D (mol %) | M (mol %) | C(mol %) |
---|---|---|---|---|
PD (95/5) | 95 | 5 | - | - |
PDM (92.5/5/2.5) | 92.5 | 5 | 2.5 | - |
PDM (90/5/5) | 90 | 5 | 5 | - |
PDC (92.5/5/2.5) | 92.5 | 5 | - | 2.5 |
PDC (90/5/5) | 90 | 5 | - | 5 |
PDC (85/5/10) | 85 | 5 | - | 10 |
P: Soy phosphatidylcholine (SPC) ; D: 1.2-Dioleyloxy-3-dimethylaminopropane (DODMA) ; M: 1,2-dipalmitoyl-sn-glycero-3-phospho((ethyl-1′,2′,3′-triazole)triethylene glycolmannose (PPM) ; C: Cholesteryl hemisuccinate (CHEMS).
2.4. Nanoparticle Characterization
2.5. Biofilm Sensitivity and Binding
2.6. Determination of Percentage Entrapment Efficiency

2.7. In Vitro Drug Release

2.8. Biofilm Studies
Biofilm Inhibition
Biofilm Eradication Experiments
Biofilm Penetration Assay
2.9. Cytotoxicity of Zwitterionic Nanoparticles
2.10. Ex Vivo Pig Skin Biofilm Eradication Model
2.11. Statistical Analysis
3. Results and Discussion
3.1. Effect of PPM and CHEMS on Zeta Potential
Figure 1
Figure 1. Characterization of the zwitterionic nanoparticles using DLS and TEM imaging. (A) Effect of PPM on zeta potential of the blank PDM formulations at different pH conditions. (B) Effect of CHEMS on zeta potential of the blank PDC formulations at different pH conditions. (C) Particle size and PDI measurements of the different antimicrobial nanoparticles. (D) Zeta potential measurements of the different antimicrobial nanoparticles at pH 7.4 (all values based on mean ± SD; n = 3). (E) Morphology of the PD 95/5, PDC 90/5/5, and PDM 90/5/5 formulation (scale bar = 500 nm).
3.2. Physicochemical Characterization of the Antimicrobial Formulations
Figure 2
Figure 2. Effect of pH, time, and storage conditions on the nanoparticles. (A) Effect of storage on the size of the different formulations. (B) Effect of storage on the zeta potential of the different formulations. (C) Effect of pH on the size of the different formulations (n = 2). (D) Effect of pH on the zeta potential of the different formulations (n = 2). (E) Size distribution of the PDM 90/5/5 formulation at pH 5.2 over 24 h. (F) Size distribution of the PDC 90/5/5 formulation at pH 5.2 over 24 h.
3.3. Surface-Adaptive Properties of the Antimicrobial Formulations and Affinity to Bacteria
3.4. Effect of Biofilm-Mimicking Conditions on Formulation Properties
Figure 3
Figure 3. Effect of biofilm matrix components and extracellular enzymes. (A) Effect of LTA on fluorescence intensity of PDMRhod 90/5/5 at pH 5.5. (B) Effect of Alexa 594 dextran on fluorescence intensity of the PDM 90/5/5 formulation. (C) Effect of lipase on the size of the PDM 90/5/5 formulations. (D) Effect of α-hemolysin on the absorbance peak of ssDNA. (E) Effect of α-hemolysin on the size of vancomycin-loaded DNA nanogel. (F) Effect of pH on S. aureus interaction with the PDM 90/5/5 formulation.
3.5. Encapsulation Efficiency and In Vitro Release Profile
Figure 4
Figure 4. Entrapment efficiency and drug release measurements. (A) Effect of surface modification on the entrapment efficiency of vancomycin (n = 2). (B) In vitro drug release measurements of free vancomycin, PD 95/5 and PDM 90/5/5 at pH 7.4. (C) In vitro drug release measurements of free vancomycin, PDM 90/5/5 in the presence of different concentrations of lipase. Values based on mean ± SD, n = 3.
3.6. In Vitro Antibiofilm Activity
Figure 5
Figure 5. In vitro antibiofilm efficacy of the PDM 90/5/5 formulations. (A) Effect of the PDM 90/5/5 formulation on biofilm inhibition and crystal violet staining image. Values based on mean ± SD, n = 3. (B) Effect of the PDM 90/5/5 formulation on early stage biofilm eradication and crystal violet staining image. Values based on mean ± SD, n = 3.
3.7. Biofilm Penetration, Biocompatibility, and Ex Vivo Efficacy
Figure 6
Figure 6. In vitro biofilm binding and penetration, biocompatibility, and ex vivo antibiofilm efficacy of the PDM 90/5/5 formulations. (A) CLSM 3D-images of GFP-labeled S. aureus biofilms after exposure PDMRho 90/5/5 (50 μg/mL) for 0, 30, and 120 min. (B) Cytotoxicity of free vancomycin and formulations against HaCaT cells. Values based on mean ± SD, n = 3. (C) Effect of the PDM 90/5/5 formulation on an ex vivo porcine biofilm model. Data presented as mean ± SD (n = 3).
4. Conclusion
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.biomac.1c01274.
Size distribution of PD 95/5, PDM 90/5/5, PDC 90/5/5, PDC 85/5/10; size distribution at physiological pH for PDM 90/5/5 and PDC 90/5/5 over 24 h; effect of formulations on fluorescent LPS at physiological and acidic pH; biofilm biomass quantification after treatment with the PDM 90/5/5 formulation (PDF)
Terms & Conditions
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Acknowledgments
The authors are thankful to Prof. Pål J. Johnsen and Dr. Elizabeth G. A. Fredheim for support with research equipment and Lipoid GmbH (Germany) for providing Lipoid S100. The authors are thankful to Tom-Ivar Eilertsen, Randi Olsen, and Augusta Hlin Aspar Sundbø at Advanced Microscopy Core Facility (AMCF) at UiT for valuable guidance on microscopy.
References
This article references 56 other publications.
- 1Karygianni, L.; Ren, Z.; Koo, H.; Thurnheer, T. Biofilm Matrixome: Extracellular Components in Structured Microbial Communities. Trends Microbiol. 2020, 28 (8), 668– 681, DOI: 10.1016/j.tim.2020.03.016Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnt1Wjsbo%253D&md5=33a8d64b007a1be3d717a9d239181935Biofilm Matrixome: Extracellular Components in Structured Microbial CommunitiesKarygianni, L.; Ren, Z.; Koo, H.; Thurnheer, T.Trends in Microbiology (2020), 28 (8), 668-681CODEN: TRMIEA; ISSN:0966-842X. (Elsevier Ltd.)A review. Biofilms consist of microbial communities embedded in a 3D extracellular matrix. The matrix is composed of a complex array of extracellular polymeric substances (EPS) that contribute to the unique attributes of biofilm lifestyle and virulence. This ensemble of chem. and functionally diverse biomols. is termed the 'matrixome'. The compn. and mechanisms of EPS matrix formation, and its role in biofilm biol., function, and microenvironment are being revealed. This perspective article highlights recent advances about the multifaceted role of the 'matrixome' in the development, phys.-chem. properties, and virulence of biofilms. We emphasize that targeting biofilm-specific conditions such as the matrixome could lead to precise and effective antibiofilm approaches. We also discuss the limited knowledge in the context of polymicrobial biofilms, and the need for more in-depth analyses of the EPS matrix in mixed communities that are assocd. with many human infectious diseases.
- 2Jamal, M.; Ahmad, W.; Andleeb, S.; Jalil, F.; Imran, M.; Nawaz, M. A.; Hussain, T.; Ali, M.; Rafiq, M.; Kamil, M. A. Bacterial biofilm and associated infections. J. Chin. Med. Assoc. 2018, 81 (1), 7– 11, DOI: 10.1016/j.jcma.2017.07.012Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M7hslWitQ%253D%253D&md5=b6b79e67ea81031bed725a3f9e25bd42Bacterial biofilm and associated infectionsJamal Muhsin; Ahmad Wisal; Hussain Tahir; Rafiq Muhammad; Andleeb Saadia; Jalil Fazal; Kamil Muhammad Atif; Imran Muhammad; Nawaz Muhammad Asif; Ali MuhammadJournal of the Chinese Medical Association : JCMA (2018), 81 (1), 7-11 ISSN:.Microscopic entities, microorganisms that drastically affect human health need to be thoroughly investigated. A biofilm is an architectural colony of microorganisms, within a matrix of extracellular polymeric substance that they produce. Biofilm contains microbial cells adherent to one-another and to a static surface (living or non-living). Bacterial biofilms are usually pathogenic in nature and can cause nosocomial infections. The National Institutes of Health (NIH) revealed that among all microbial and chronic infections, 65% and 80%, respectively, are associated with biofilm formation. The process of biofilm formation consists of many steps, starting with attachment to a living or non-living surface that will lead to formation of micro-colony, giving rise to three-dimensional structures and ending up, after maturation, with detachment. During formation of biofilm several species of bacteria communicate with one another, employing quorum sensing. In general, bacterial biofilms show resistance against human immune system, as well as against antibiotics. Health related concerns speak loud due to the biofilm potential to cause diseases, utilizing both device-related and non-device-related infections. In summary, the understanding of bacterial biofilm is important to manage and/or to eradicate biofilm-related diseases. The current review is, therefore, an effort to encompass the current concepts in biofilm formation and its implications in human health and disease.
- 3Sharma, D.; Misba, L.; Khan, A. U. Antibiotics versus biofilm: an emerging battleground in microbial communities. Antimicrob Resist Infect Control 2019, 8, 76, DOI: 10.1186/s13756-019-0533-3Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3M7pvFylsw%253D%253D&md5=3bf1bde023c0e69c1b9df9e1b3116504Antibiotics versus biofilm: an emerging battleground in microbial communitiesSharma Divakar; Misba Lama; Khan Asad UAntimicrobial resistance and infection control (2019), 8 (), 76 ISSN:.Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics. It is one of the major causes of infection persistence especially in nosocomial settings through indwelling devices. Quorum sensing plays an important role in regulating the biofilm formation. There are many approaches being used to control infections by suppressing its formation but CRISPR-CAS (gene editing technique) and photo dynamic therapy (PDT) are proposed to be used as therapeutic approaches to subside bacterial biofim infections, especially caused by deadly drug resistant bad bugs.
- 4Duan, Y.; He, K.; Zhang, G.; Hu, J. Photoresponsive Micelles Enabling Codelivery of Nitric Oxide and Formaldehyde for Combinatorial Antibacterial Applications. Biomacromolecules 2021, 22 (5), 2160– 2170, DOI: 10.1021/acs.biomac.1c00251Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXptFCnsL4%253D&md5=66fec25a001cf0b9b50f7bfaf4af943cPhotoresponsive Micelles Enabling Codelivery of Nitric Oxide and Formaldehyde for Combinatorial Antibacterial ApplicationsDuan, Yutian; He, Kewu; Zhang, Guoying; Hu, JinmingBiomacromolecules (2021), 22 (5), 2160-2170CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)It is of particular interest to develop new antibacterial agents with low risk of drug resistance development and low toxicity toward mammalian cells to combat pathogen infections. Although gaseous signaling mols. (GSMs) such as nitric oxide (NO) and formaldehyde (FA) have broad-spectrum antibacterial performance and the low propensity of drug resistance development, many previous studies heavily focused on nanocarriers capable of delivering only one GSM. Herein, we developed a micellar nanoparticle platform that can simultaneously deliver NO and FA under visible light irradn. An amphiphilic diblock copolymer of poly(ethylene oxide)-b-poly(4-((2-nitro-5-(((2-nitrobenzyl)oxy)methoxy)benzyl)(nitroso)amino)benzyl methacrylate) (PEO-b-PNNBM) was successfully synthesized through atom transfer radical polymn. (ATRP). The resulting diblock copolymer self-assembled into micellar nanoparticles without premature NO and FA leakage, whereas they underwent phototriggered disassembly with the corelease of NO and FA. We showed that the NO- and FA-releasing micellar nanoparticles exhibited a combinatorial antibacterial performance, efficiently killing both Gram-neg. (e.g., Escherichia coli) and Gram-pos. (e.g., Staphylococcus aureus) bacteria with low toxicity to mammalian cells and low hemolytic property. This work provides new insights into the development of GSM-based antibacterial agents.
- 5Koo, H.; Allan, R. N.; Howlin, R. P.; Stoodley, P.; Hall-Stoodley, L. Targeting microbial biofilms: current and prospective therapeutic strategies. Nat. Rev. Microbiol. 2017, 15 (12), 740– 755, DOI: 10.1038/nrmicro.2017.99Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFCqtrjP&md5=57c9f42f90e3e281294ffa92beab6bbcTargeting microbial biofilms: current and prospective therapeutic strategiesKoo, Hyun; Allan, Raymond N.; Howlin, Robert P.; Stoodley, Paul; Hall-Stoodley, LuanneNature Reviews Microbiology (2017), 15 (12), 740-755CODEN: NRMACK; ISSN:1740-1526. (Nature Research)A review. Biofilm formation is a key virulence factor for a wide range of microorganisms that cause chronic infections. The multifactorial nature of biofilm development and drug tolerance imposes great challenges for the use of conventional antimicrobials and indicates the need for multi-targeted or combinatorial therapies. In this Review, we focus on current therapeutic strategies and those under development that target vital structural and functional traits of microbial biofilms and drug tolerance mechanisms, including the extracellular matrix and dormant cells. We emphasize strategies that are supported by in vivo or ex vivo studies, highlight emerging biofilm-targeting technologies and provide a rationale for multi-targeted therapies aimed at disrupting the complex biofilm microenvironment.
- 6Khan, J.; Tarar, S. M.; Gul, I.; Nawaz, U.; Arshad, M. Challenges of antibiotic resistance biofilms and potential combating strategies: a review. 3 Biotech 2021, 11 (4), 169, DOI: 10.1007/s13205-021-02707-wGoogle Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3sfntFGhsw%253D%253D&md5=0d3f60acb038faddba05e3d6e183004fChallenges of antibiotic resistance biofilms and potential combating strategies: a reviewKhan Javairia; Tarar Sumbal Mudassar; Arshad Muhammad; Gul Iram; Nawaz Uzam3 Biotech (2021), 11 (4), 169 ISSN:2190-572X.In this modern era, medicine is facing many alarming challenges. Among different challenges, antibiotics are gaining importance. Recent years have seen unprecedented increase in knowledge and understanding of various factors that are root cause of the spread and development of resistance in microbes against antibiotics. The infection results in the formation of microbial colonies which are termed as biofilms. However, it has been found that a multiple factors contribute in the formation of antimicrobial resistance. Due to higher dose of Minimum Bactericidal Concentration (MBC) as well as of Minimum Inhibitory Concentration (MIC), a large batch of antibiotics available today are of no use as they are ineffective against infections. Therefore, to control infections, there is dire need to adopt alternative treatment for biofilm infection other than antibiotics. This review highlights the latest techniques that are being used to cure the menace of biofilm infections. A wide range of mechanisms has been examined with particular attention towards avenues which can be proved fruitful in the treatment of biofilms. Besides, newer strategies, i.e., matrix centered are also discussed as alternative therapeutic techniques including modulating microbial metabolism, matrix degrading enzyme, photodynamic therapy, natural compounds quorum sensing and nanotechnology which are being used to disrupt extra polymeric substances (EPS) matrix of desired bacterial biofilms.
- 7Le, H.; Arnoult, C.; De, E.; Schapman, D.; Galas, L.; Le Cerf, D.; Karakasyan, C. Antibody-Conjugated Nanocarriers for Targeted Antibiotic Delivery: Application in the Treatment of Bacterial Biofilms. Biomacromolecules 2021, 22 (4), 1639– 1653, DOI: 10.1021/acs.biomac.1c00082Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXmtFOhurw%253D&md5=63005cbd75276c74cb9ae06c6c9597c1Antibody-Conjugated Nanocarriers for Targeted Antibiotic Delivery: Application in the Treatment of Bacterial BiofilmsLe, Hung; Arnoult, Christophe; De, Emmanuelle; Schapman, Damien; Galas, Ludovic; Le Cerf, Didier; Karakasyan, CaroleBiomacromolecules (2021), 22 (4), 1639-1653CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)Conventional antibiotic treatment is in most cases insufficient to eradicate biofilm-related infections, resulting in high risk of treatment failure and recurrent infections. Recent studies have shown that novel methods of antibiotic delivery can improve clin. outcomes and reduce the emergence of antibiotic resistance. The objectives of this work were to develop and evaluate a targeting nanocarrier system that enables effective delivery of antimicrobial drugs to Staphylococcus aureus, a commonly virulent human pathogen. For this purpose, we first prepd. a formulation of polymeric nanoparticles (NPs) suitable for encapsulation and sustained release of antibiotics. A specific antibody against S. aureus was used as a targeting ligand and was covalently immobilized onto the surface of nanoparticulate materials. It was demonstrated that the targeting NPs preferentially bound S. aureus cells and presented an elevated accumulation in the S. aureus biofilm. Compared to free-form antibiotic, the antibiotic-loaded targeting NPs significantly enhanced in vitro bactericidal activity against S. aureus both in planktonic and biofilm forms. Using a mouse infection model, we obsd. improved therapeutic efficacy of these antibiotic-loaded NPs after a single i.v. administration. Taken together, our studies show that the targeting nanoparticulate system could be a promising strategy to enhance the biodistribution of antibiotics and thereby improve their efficacy.
- 8Sun, Y.; Liu, Y.; Zhang, B.; Shi, S.; Zhang, T.; Zhao, D.; Tian, T.; Li, Q.; Lin, Y. Erythromycin loaded by tetrahedral framework nucleic acids are more antimicrobial sensitive against Escherichia coli (E. coli). Bioact Mater. 2021, 6 (8), 2281– 2290, DOI: 10.1016/j.bioactmat.2020.12.027Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtFKjtrrE&md5=87bde11fa4efdc972fa55a07a02864bbErythromycin loaded by tetrahedral framework nucleic acids are more antimicrobial sensitive against Escherichia coli (E. coli)Sun, Yue; Liu, Yuhao; Zhang, Bowen; Shi, Shirong; Zhang, Tao; Zhao, Dan; Tian, Taoran; Li, Qirong; Lin, YunfengBioactive Materials (2021), 6 (8), 2281-2290CODEN: BMIAD4; ISSN:2452-199X. (Elsevier B.V.)Erythromycin is a commonly used broad-spectrum antibiotic, but resistance to this antibiotic makes its use less effective. Considerable efforts, beside finding alternatives, are needed to enhance its antimicrobial effect and stability against bacteria. Tetrahedral framework nucleic acids (tFNAs), a novel delivery vehicle with a three-dimensional nanostructure, have been studied as a carrying platform of antineoplastic drugs. In this study, the use of tFNAs in delivering erythromycin into Escherichia coli (E. coli) was investigated for the first time. The tFNAs vehicle increased the bacterial uptake of erythromycin and promoted membrane destabilization. Moreover, it increased the permeability of the bacterial cell wall, and reduced drug resistance by improving the movement of the drug across the membrane. The tFNAs-based delivery system enhanced the effects of erythromycin against E. coli. It may therefore provide an effective delivery vehicle for erythromycin in targeting antibiotic-resistant bacteria with thick cell wall.
- 9Obuobi, S.; Mayandi, V.; Nor, N. A. M.; Lee, B. J.; Lakshminarayanan, R.; Ee, P. L. R. Nucleic acid peptide nanogels for the treatment of bacterial keratitis. Nanoscale 2020, 12 (33), 17411– 17425, DOI: 10.1039/D0NR03095CGoogle Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsF2ntbzP&md5=45781ef2b9111b69331af69e94b59a5fNucleic acid peptide nanogels for the treatment of bacterial keratitisObuobi, Sybil; Mayandi, Venkatesh; Nor, Nurul Azlyn Mohd; Lee, Benedict Jiasheng; Lakshminarayanan, Rajamani; Ee, Pui Lai RachelNanoscale (2020), 12 (33), 17411-17425CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Cage-shaped nucleic acid nanocarriers are promising mol. scaffolds for the organization of polypeptides. However, there is an unmet need for facile loading strategies that truly emulate nature's host-guest systems to drive encapsulation of antimicrobial peptides without loss of biol. activity. Herein, we develop DNA nanogels with rapid in situ loading of L12 peptide during the thermal annealing process. By leveraging the binding affinity of L12 to the polyanionic core, we successfully confine the AMPs within the DNA nanogel. We report that the thermostability of L12 in parallel with the high encapsulation efficiency, low toxicity and sustained drug release of the pre-loaded L12 nanogels can be translated into significant antimicrobial activity. Using an S. aureus model of infectious bacterial keratitis, we observe fast resoln. of clin. symptoms and significant redn. of bacterial bioburden. Collectively, this study paves the way for the development of DNA nanocarriers for caging AMPs with immense significance to address the rise of resistance.
- 10Chi, Q. J.; Yang, Z. C.; Xu, K.; Wang, C. L.; Liang, H. P. DNA Nanostructure as an Efficient Drug Delivery Platform for Immunotherapy. Front. Pharmacol. 2020, 10, 1– 17, DOI: 10.3389/fphar.2019.01585Google ScholarThere is no corresponding record for this reference.
- 11Nicolson, F.; Ali, A.; Kircher, M. F.; Pal, S. DNA Nanostructures and DNA-Functionalized Nanoparticles for Cancer Theranostics. Adv. Sci. (Weinh) 2020, 7 (23), 2001669, DOI: 10.1002/advs.202001669Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3szmtF2lsQ%253D%253D&md5=4ad5e33a240fc39bd664fafc62c22a2cDNA Nanostructures and DNA-Functionalized Nanoparticles for Cancer TheranosticsNicolson Fay; Kircher Moritz F; Nicolson Fay; Kircher Moritz F; Ali Akbar; Pal Suchetan; Kircher Moritz FAdvanced science (Weinheim, Baden-Wurttemberg, Germany) (2020), 7 (23), 2001669 ISSN:2198-3844.In the last two decades, DNA has attracted significant attention toward the development of materials at the nanoscale for emerging applications due to the unparalleled versatility and programmability of DNA building blocks. DNA-based artificial nanomaterials can be broadly classified into two categories: DNA nanostructures (DNA-NSs) and DNA-functionalized nanoparticles (DNA-NPs). More importantly, their use in nanotheranostics, a field that combines diagnostics with therapy via drug or gene delivery in an all-in-one platform, has been applied extensively in recent years to provide personalized cancer treatments. Conveniently, the ease of attachment of both imaging and therapeutic moieties to DNA-NSs or DNA-NPs enables high biostability, biocompatibility, and drug loading capabilities, and as a consequence, has markedly catalyzed the rapid growth of this field. This review aims to provide an overview of the recent progress of DNA-NSs and DNA-NPs as theranostic agents, the use of DNA-NSs and DNA-NPs as gene and drug delivery platforms, and a perspective on their clinical translation in the realm of oncology.
- 12Hui, L.; Xu, A.; Liu, H. DNA-Based Nanofabrication for Antifouling Applications. Langmuir 2019, 35 (38), 12543– 12549, DOI: 10.1021/acs.langmuir.9b01569Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1ajtbrL&md5=6849132a1f3e80cf7cce572282fd2ce6DNA-Based Nanofabrication for Antifouling ApplicationsHui, Liwei; Xu, Anqin; Liu, HaitaoLangmuir (2019), 35 (38), 12543-12549CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)This paper reports antifouling properties of nanostructured SiO2 substrates patterned by DNA lithog. We used DNA triangle nanostructures as templates to produce triangular-shaped trenches ca. 130 nm in size on SiO2 surfaces. Using B. subtilis as a bacterial model, we found that such nanopatterned surface showed a 75% redn. in bacterial adhesion and 72% redn. in biofilm d. at 35% surface coverage of the nanoscale triangular trenches. DNA-based nanofabrication can produce high-resoln. designer patterns, but aligning these patterns has been one of the major tech. challenges for its applications in nanoelectronics. This work demonstrates the potential of DNA-based nanofabrication in antifouling applications, where surface patterning of micro/nanostructures is required but not their precise alignment.
- 13Mela, I.; Vallejo-Ramirez, P. P.; Makarchuk, S.; Christie, G.; Bailey, D.; Henderson, R. M.; Sugiyama, H.; Endo, M.; Kaminski, C. F. DNA Nanostructures for Targeted Antimicrobial Delivery. Angew. Chem., Int. Ed. 2020, 59 (31), 12698– 12702, DOI: 10.1002/anie.202002740Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXpsl2ksbo%253D&md5=287d9b69f966370aa62e0e2eb247affcDNA Nanostructures for Targeted Antimicrobial DeliveryMela, Ioanna; Vallejo-Ramirez, Pedro P.; Makarchuk, Stanislaw; Christie, Graham; Bailey, David; Henderson, Robert M.; Sugiyama, Hiroshi; Endo, Masayuki; Kaminski, Clemens F.Angewandte Chemie, International Edition (2020), 59 (31), 12698-12702CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)We report the use of DNA origami nanostructures, functionalized with aptamers, as a vehicle for delivering the antibacterial enzyme lysozyme in a specific and efficient manner. We test the system against Gram-pos. (Bacillus subtilis) and Gram-neg. (Escherichia coli) targets. We use direct stochastic optical reconstruction microscopy (dSTORM) and at. force microscopy (AFM) to characterize the DNA origami nanostructures and structured illumination microscopy (SIM) to assess the binding of the origami to the bacteria. We show that treatment with lysozyme-functionalized origami slows bacterial growth more effectively than treatment with free lysozyme. Our study introduces DNA origami as a tool in the fight against antibiotic resistance, and our results demonstrate the specificity and efficiency of the nanostructure as a drug delivery vehicle.
- 14Hu, S. Q.; Yi, T. T.; Huang, Z. C.; Liu, B. W.; Wang, J. X.; Yi, X. Y.; Liu, J. W. Etching silver nanoparticles using DNA. Mater. Horiz. 2019, 6 (1), 155– 159, DOI: 10.1039/C8MH01126EGoogle Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVOjtLbJ&md5=d24295d5c6f42e2a3a5501e5415f02bcEtching silver nanoparticles using DNAHu, Shengqiang; Yi, Tiantian; Huang, Zhicheng; Liu, Biwu; Wang, Jianxiu; Yi, Xinyao; Liu, JuewenMaterials Horizons (2019), 6 (1), 155-159CODEN: MHAOBM; ISSN:2051-6355. (Royal Society of Chemistry)While DNA has been widely used for directing the growth and assembly of nanomaterials, the reverse reaction, etching nanoparticles using DNA, has yet to be demonstrated. We herein communicate that poly-cytosine (poly-C) DNA can efficiently etch silver nanoparticles (AgNPs) followed by Ostwald ripening at higher DNA concns. The etching process was precisely controlled by varying the length, sequence, and concn. of DNA, and the no. of consecutive cytosines is particularly important for the efficacy of etching. In addn. to spherical AgNPs, etching also occurred for silver nanoplates displaying interesting color changes. Compared to other chem. etching agents such as H2O2 and ferricyanide, DNA is highly biocompatible, allowing biol. applications. Poly-C etching enhanced the cytotoxicity of AgNPs against cancer cells, and Gram-pos. and Gram-neg. bacterial cells. This study will stimulate many related studies in DNA nanotechnol., bioanal. sensors and nanomedicine.
- 15Obuobi, S.; Julin, K.; Fredheim, E. G. A.; Johannessen, M.; Skalko-Basnet, N. Liposomal delivery of antibiotic loaded nucleic acid nanogels with enhanced drug loading and synergistic anti-inflammatory activity against S. aureus intracellular infections. J. Controlled Release 2020, 324, 620– 632, DOI: 10.1016/j.jconrel.2020.06.002Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtFOhsbvJ&md5=84749b577c27b50e6b7ac743d6f68c9eLiposomal delivery of antibiotic loaded nucleic acid nanogels with enhanced drug loading and synergistic anti-inflammatory activity against S. aureus intracellular infectionsObuobi, Sybil; Julin, Kjersti; Fredheim, Elizabeth G. A.; Johannessen, Mona; Skalko-Basnet, NatasaJournal of Controlled Release (2020), 324 (), 620-632CODEN: JCREEC; ISSN:0168-3659. (Elsevier B.V.)The persistence of Staphylococcus aureus has been accredited to its ability to escape immune response via host cell invasion. Despite the efficacy of many antibiotics against S. aureus, the high extracellular concns. of conventional antibiotics required for bactericidal activity is limited by their low cellular accumulation and poor intracellular retention. While nanocarriers have received tremendous attention for antibiotic delivery against persistent pathogens, they suffer daunting challenges such as low drug loading, poor retention and untimely release of hydrophilic cargos. Here, a hybrid system (Van_DNL) is fabricated wherein nucleic acid nanogels are caged within a liposomal vesicle for antibiotic delivery. The central principle of this approach relies on exploiting non-covalent electrostatic interactions between cationic cargos and polyanionic DNA to immobilize antibiotics and enable precise temporal release against intracellular S. aureus. In vitro characterization of Van_DNL revealed a stable homogenous formulation with circular morphol. and enhanced vancomycin loading efficiency. The hybrid system significantly sustained the release of vancomycin over 24 h compared to liposomal or nanogel controls. Under enzymic conditions relevant to S. aureus infections, lipase triggered release of vancomycin was obsd. from the hybrid. While using Van_DNL to treat S. aureus infected macrophages, a dose dependent redn. in intracellular bacterial load was obsd. over 24 h and exposure to Van_DNL for 48 h caused negligible cellular toxicity. Pre-treatment of macrophages with the antimicrobial hybrid resulted in a strong anti-inflammatory activity in synergy with vancomycin following endotoxin stimulation. Conceptually, these findings highlight these hybrids as a unique and universal platform for synergistic antimicrobial and anti-inflammatory therapy against persistent infections.
- 16Pang, Y. Y.; Schwartz, J.; Thoendel, M.; Ackermann, L. W.; Horswill, A. R.; Nauseef, W. M. agr-Dependent interactions of Staphylococcus aureus USA300 with human polymorphonuclear neutrophils. J. Innate Immun. 2010, 2 (6), 546– 59, DOI: 10.1159/000319855Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht12lurzE&md5=298816719f91b27d01ad917c45131fa8agr-Dependent Interactions of Staphylococcus aureus USA300 with Human Polymorphonuclear NeutrophilsPang, Yun Yun; Schwartz, Jamie; Thoendel, Matthew; Ackermann, Laynez W.; Horswill, Alexander R.; Nauseef, William M.Journal of Innate Immunity (2010), 2 (6), 546-559CODEN: JIIOB2; ISSN:1662-811X. (S. Karger AG)The emergence of serious infections due to community-assocd. methicillin-resistant Staphylococcus aureus (CA-MRSA) has fueled interest in the contributions of specific staphylococcal virulence factors to clin. disease. To assess the contributions of agr-dependent factors to the fate of organisms in polymorphonuclear neutrophils (PMN), we examd. the consequences for organism and host cells of feeding PMN with wild-type CA-MRSA (LAC) or CA-MRSA (LAC agr KO) at different multiplicities of infection (MOIs). Phagocytosed organisms rapidly increased the transcription of RNAIII in a time- and MOI-dependent fashion; extracellular USA300 (LAC) did not increase RNAIII expression despite having the capacity to respond to autoinducing peptide-enriched culture medium. HOCl-mediated damage and intracellular survival were the same in the wild-type and USA300 (LAC agr KO). PMN lysis by ingested USA300 (LAC) was time- and MOI-dependent and, at MOIs >1, required α-hemolysin (hla) as USA300 (LAC agr KO) and USA300 (LAC hla KO) promoted PMN lysis only at high MOIs. Taken together, these data demonstrate activation of the agr operon in human PMN with the subsequent prodn. of α-hemolysin and PMN lysis. The extent to which these events in the phagosomes of human PMN contribute to the increased morbidity and mortality of infections with USA300 (LAC) merits further study.
- 17Obuobi, S.; Tay, H. K.; Tram, N. D. T.; Selvarajan, V.; Khara, J. S.; Wang, Y.; Ee, P. L. R. Facile and efficient encapsulation of antimicrobial peptides via crosslinked DNA nanostructures and their application in wound therapy. J. Controlled Release 2019, 313, 120– 130, DOI: 10.1016/j.jconrel.2019.10.013Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitVelurrI&md5=285a216b62ad656e022d199751ce2e42Facile and efficient encapsulation of antimicrobial peptides via crosslinked DNA nanostructures and their application in wound therapyObuobi, Sybil; Tay, Hilda Kai-Lin; Tram, Nhan Dai Thien; Selvarajan, Vanitha; Khara, Jasmeet Singh; Wang, Ying; Ee, Pui Lai RachelJournal of Controlled Release (2019), 313 (), 120-130CODEN: JCREEC; ISSN:0168-3659. (Elsevier B.V.)There is growing interest in the development of nucleic acid nanostructures as smart functional materials for applications in drug delivery. Inspired by the diverse phys. interactions that exist in nature, crosslinked DNA nanostructures can serve as attractive affinity binding networks that interact with therapeutic cargos or living cells. Herein we report a strategy that addresses the challenges of topical oligopeptide therapy by exploiting high binding affinity between polyanionic DNA nanostructures and cationic antimicrobial peptides (AMPs) to fabricate hydrogels that release a model antimicrobial L12 peptide in response to pathogenic S. aureus infections. We further demonstrated controlled peptide release profiles via the DNA hydrogels that were biocompatible and delivered superior antimicrobial activity against nuclease-releasing susceptible and methicillin-resistant S. aureus infections. Single application of the L12-loaded DNA hydrogels on porcine explant S. aureus infections revealed potent efficacy after 24 h. As a result of the capacity of the crosslinked DNA nanostructures to elicit a strong anti-inflammatory response, in vivo treatment of mice excision wounds translated into faster healing rates. Overall, the crosslinked DNA nanostructures reported in this study offer significant advantage as functional wound dressings and their future adaptation holds equally great promise for the delivery of cationic antimicrobials.
- 18Singh, N.; Romero, M.; Travanut, A.; Monteiro, P. F.; Jordana-Lluch, E.; Hardie, K. R.; Williams, P.; Alexander, M. R.; Alexander, C. Dual bioresponsive antibiotic and quorum sensing inhibitor combination nanoparticles for treatment of Pseudomonas aeruginosa biofilms in vitro and ex vivo. Biomater. Sci. 2019, 7 (10), 4099– 4111, DOI: 10.1039/C9BM00773CGoogle Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsVGgsrjN&md5=8120b77dfb09868ceb0c926ad411a23dDual bioresponsive antibiotic and quorum sensing inhibitor combination nanoparticles for treatment of Pseudomonas aeruginosa biofilms in vitro and ex vivoSingh, Nishant; Romero, Manuel; Travanut, Alessandra; Monteiro, Patricia F.; Jordana-Lluch, Elena; Hardie, Kim R.; Williams, Paul; Alexander, Morgan R.; Alexander, CameronBiomaterials Science (2019), 7 (10), 4099-4111CODEN: BSICCH; ISSN:2047-4849. (Royal Society of Chemistry)Many debilitating infections result from persistent microbial biofilms that do not respond to conventional antibiotic regimens. A potential method to treat such chronic infections is to combine agents which interfere with bacterial biofilm development together with an antibiotic in a single formulation. Here, we explore the use of a new bioresponsive polymer formulation derived from specifically modified alginate nanoparticles (NPs) in order to deliver ciprofloxacin (CIP) in combination with the quorum sensing inhibitor (QSI) 3-amino-7-chloro-2-nonylquinazolin-4(3H)-one (ACNQ) to mature Pseudomonas aeruginosa biofilms. The alginate NPs were engineered to incorporate a pH-responsive linker between the polysaccharide backbone and the QSI, and to encapsulate CIP via charge-charge interactions of the pos.-charged drug with the carboxyl residues of the alginate matrix. In this way, a dual-action release of antibiotic and QSI was designed for the low-pH regions of a biofilm, involving cleavage of the QSI-linker to the alginate matrix and reduced charge-charge interactions between CIP and the polysaccharide as the alginate carboxyl side-chains protonated. When tested in a biofilm model the concomitant release of CIP + QSI from the pH-responsive nanoparticles significantly reduced the viability of the biofilm compared with CIP treatment alone. In addn., the alginate NPs were shown to penetrate deeply into P. aeruginosa biofilms, which we attribute in part to the charges of the NPs and the release of the QSI agent. Finally, we tested the formulation in both a 2D keratinocyte and a 3D ex vivo skin infection model. The dual-action bio-responsive QSI and CIP release nanoparticles effectively cleared the infection in the latter, suggesting considerable promise for combination therapeutics which prevent biofilm formation as well as effectively killing mature P. aeruginosa biofilms.
- 19Hafez, I. M.; Cullis, P. R. Cholesteryl hemisuccinate exhibits pH sensitive polymorphic phase behavior. Biochim. Biophys. Acta, Biomembr. 2000, 1463 (1), 107– 14, DOI: 10.1016/S0005-2736(99)00186-8Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXjtV2ntQ%253D%253D&md5=bb607053ffb66c261b29b02d111dc5f4Cholesteryl hemisuccinate exhibits pH sensitive polymorphic phase behaviorHafez, I. M.; Cullis, P. R.Biochimica et Biophysica Acta, Biomembranes (2000), 1463 (1), 107-114CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)Cholesteryl hemisuccinate (CHEMS) is an acidic cholesterol ester that self-assembles into bilayers in alk. and neutral aq. media and is commonly employed in mixts. with dioleoylphosphatidylethanolamine (DOPE) to form 'pH sensitive' fusogenic vesicles. We show here that CHEMS itself exhibits pH sensitive polymorphism. This is evident from the fusogenic properties of large unilamellar vesicles (LUV) composed of CHEMS and direct visualization employing freeze-fracture electron microscopy. Below pH 4.3, LUV composed of CHEMS undergo fusion as monitored by lipid mixing assays and freeze-fracture electron micrographs reveal the characteristic striated signature of H‖ phase lipid. It is suggested that the pH dependent phase preferences of CHEMS contribute to the pH sensitivity of LUV composed of mixts. of CHEMS and DOPE.
- 20Sun, X.; Zhang, Z. Optimizing the novel formulation of liposome-polycation-DNA complexes (LPD) by central composite design. Arch. Pharmacal Res. 2004, 27 (7), 797– 805, DOI: 10.1007/BF02980151Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmsFeru78%253D&md5=b5a48a01a6cb5754424485b08d06a5dfOptimizing the novel formulation of liposome-polycation-DNA complexes (LPD) by central composite designSun, Xun; Zhang, ZhirongArchives of Pharmacal Research (2004), 27 (7), 797-805CODEN: APHRDQ; ISSN:0253-6269. (Pharmaceutical Society of Korea)LPD vectors are non-viral vehicles for gene delivery comprised of polycation-condensed plasmid DNA and liposomes. Here, we described a novel anionic LPD formulation contg. protamine-DNA complexes and pH sensitive liposomes composed of DOPE and cholesteryl hemisuccinate (Chems). Central composite design (CCD) was employed to optimize stable LPD formulation with small particle size. A three factor, five-level CCD design was used for the optimization procedure, with the wt. ratio of protamine/DNA (X1), the wt. ratio of Chems/DNA (X2) and the molar ratio of Chems/DOPE in the anionic liposomes (X3) as the independent variables. LPD size (Y1) and LPD protection efficiency against nuclease (Y2) were response variables. Zeta potential detn. was utilized to define the exptl. design region. Based on exptl. design, responses for the 15 formulations were obtained. Math. equations and response surface plots were used to relate the dependent and independent variables. The math. model predicted optimized X1-X3 levels that achieve the desired particle size and the protection efficiency against nuclease. According to these levels, an optimized LPD formulation was prepd., resulting in a particle size of 185.3 nm and protection efficiency of 80.22%.
- 21Fillion, P.; Desjardins, A.; Sayasith, K.; Lagace, J. Encapsulation of DNA in negatively charged liposomes and inhibition of bacterial gene expression with fluid liposome-encapsulated antisense oligonucleotides. Biochim. Biophys. Acta, Biomembr. 2001, 1515 (1), 44– 54, DOI: 10.1016/S0005-2736(01)00392-3Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXnsVSmtLw%253D&md5=6021dae68388bf2b42c60a8cf1064005Encapsulation of DNA in negatively charged liposomes and inhibition of bacterial gene expression with fluid liposome-encapsulated antisense oligonucleotidesFillion, P.; Desjardins, A.; Sayasith, K.; Lagace, J.Biochimica et Biophysica Acta, Biomembranes (2001), 1515 (1), 44-54CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)Antisense therapy for the treatment of bacterial infections is a very attractive alternative to overcome drug resistance problems. However, the penetration of antisense oligonucleotides into bacterial cells is a major huddle that has delayed research and application in this field. In the first part of this study, we defined efficient conditions to encapsulate plasmid DNA and antisense oligonucleotides in a fluid neg. charged liposome. Subsequently, we evaluated the potential of liposome-encapsulated antisense oligonucleotides to penetrate the bacterial outer membrane and to inhibit gene expression in bacteria. It was found that 48.9±12% and 43.5±4% of the purified plasmid DNA and antisense oligonucleotides were resp. encapsulated in the liposomes. Using fluorescence-activated cell sorting anal., it was shown, after subtraction of the fluorescence values due to the aggregation phenomenon measured at 4°, that about 57% of bacterial cells had integrated the encapsulated antisense oligonucleotides whereas values for free antisenses were negligible. The uptake of the encapsulated anti-lacZ antisense oligonucleotides resulted in a 42% redn. of β-galactosidase compared to 9% and 6% for the encapsulated mismatch antisense oligonucleotides and the free antisense oligonucleotides, resp. This work shows that it is possible to encapsulate relatively large quantities of neg. charged mols. in neg. fluid liposomes and suggests that fluid liposomes could be used to deliver nucleic acids in bacteria to inhibit essential bacterial genes.
- 22Mozafari, M. R.; Hasirci, V. Mechanism of calcium ion induced multilamellar vesicle-DNA interaction. J. Microencapsulation 1998, 15 (1), 55– 65, DOI: 10.3109/02652049809006835Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXhs1KltLk%253D&md5=392406d6ec0bbf0acf7f6741521873c1Mechanism of calcium ion induced multilamellar vesicle-DNA interactionMozafari, M. R.; Hasirci, V.Journal of Microencapsulation (1998), 15 (1), 55-65CODEN: JOMIEF; ISSN:0265-2048. (Taylor & Francis Ltd.)The effect of Ca2+ on the DNA interaction with anionic and neutral multi-lamellar vesicles (MLV) has been investigated. DNA from wheat (Triticum aestivum) was introduced to a suspension of MLV, composed of phosphatidylcholine (PC):dicetylphosphate (DCP):cholesterol (CHOL) at different molar ratios, to which Ca2+ (5-75 mM) was subsequently added. Indication of aggregation and/or fusion was obtained via light-scattering examn. following the addn. of Ca2+ and DNA to the MLV medium. Using a UV spectrophotometric assay, it was obsd. that although DNA alone has no effect on neg. charged MLV, it enhances liposomal interaction in the presence of calcium ions. The minimal Ca2+ concn. required to promote the interaction was detected to be 10 mM, and the highest level of interaction was obsd. at 75 mM. The aggregation/fusion of vesicles was detected for uncharged MLV (with no DCP in their structure), as well as for the anionic ones contg. c. 10% CHOL, but not for anionic MLV contg. 40% CHOL. This is explained in terms of cholesterol decreasing the membrane fluidity (above the Tc of components) as a result of which more rigid vesicles become less prone to aggregation/fusion interactions.
- 23Grit, M.; Crommelin, J. A. Chemical-Stability of Liposomes - Implications for Their Physical Stability. Chem. Phys. Lipids 1993, 64 (1–3), 3– 18, DOI: 10.1016/0009-3084(93)90053-6Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXmslyntrs%253D&md5=41e621a6f027d4b2a135ec55a8f2edd8Chemical stability of liposomes: Implications for their physical stabilityGrit, Mustafa; Crommelin, Daan J. A.Chemistry and Physics of Lipids (1993), 64 (1-3), 3-18CODEN: CPLIA4; ISSN:0009-3084.A review with 56 refs.; in the first part of this article, chem. and phys. stability of aq. liposome dispersions have been addressed. Chem. stability of phospholipids has been considered in two parts: oxidn. and hydrolysis. Major attention has been paid to hydrolysis kinetics of phospholipids as a function of pH, temp., buffer concn. and ionic strength. Furthermore, the effect of chain length, head group, state of aggregation, addn. of cholesterol and presence of charge on the hydrolysis kinetics of phospholipids has been dealt with. In the second part phys. stability of chem. degraded liposome dispersions has been evaluated. In the final part quality control assays for liposome dispersions is presented and a HPLC method with a refractive index detector for the anal. of phospholipids from aq. liposome dispersions is described.
- 24Bhattacharjee, S. DLS and zeta potential - What they are and what they are not?. J. Controlled Release 2016, 235, 337– 351, DOI: 10.1016/j.jconrel.2016.06.017Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFOgt73O&md5=50555ae8bc84aff2dc92b1c2d24dcf80DLS and zeta potential - What they are and what they are not?Bhattacharjee, SouravJournal of Controlled Release (2016), 235 (), 337-351CODEN: JCREEC; ISSN:0168-3659. (Elsevier B.V.)A review. Adequate characterization of NPs (nanoparticles) is of paramount importance to develop well defined nanoformulations of therapeutic relevance. Detn. of particle size and surface charge of NPs are indispensable for proper characterization of NPs. DLS (dynamic light scattering) and ZP (zeta potential) measurements have gained popularity as simple, easy and reproducible tools to ascertain particle size and surface charge. Unfortunately, on practical grounds plenty of challenges exist regarding these two techniques including inadequate understanding of the operating principles and dealing with crit. issues like sample prepn. and interpretation of the data. As both DLS and ZP have emerged from the realms of phys. colloid chem. - it is difficult for researchers engaged in nanomedicine research to master these two techniques. Addnl., there is little literature available in drug delivery research which offers a simple, concise account on these techniques. This review tries to address this issue while providing the fundamental principles of these techniques, summarizing the core math. principles and offering practical guidelines on tackling commonly encountered problems while running DLS and ZP measurements. Finally, the review tries to analyze the relevance of these two techniques from translatory perspective.
- 25Smistad, G.; Jacobsen, J.; Sande, S. A. Multivariate toxicity screening of liposomal formulations on a human buccal cell line. Int. J. Pharm. 2007, 330 (1–2), 14– 22, DOI: 10.1016/j.ijpharm.2006.08.044Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntFSgtQ%253D%253D&md5=543a91785cf7f58a0931c44831fe4751Multivariate toxicity screening of liposomal formulations on a human buccal cell lineSmistad, Gro; Jacobsen, Jette; Sande, Sverre A.International Journal of Pharmaceutics (2007), 330 (1-2), 14-22CODEN: IJPHDE; ISSN:0378-5173. (Elsevier Ltd.)The influence of various formulation factors on the in vitro cellular toxicity of liposomes on human buccal cells (TR146), were studied by using the concept of statistical exptl. design and multivariate evaluation. The factors investigated were the type of main phospholipid (egg-PC, DMPC, DPPC), lipid concn., the type of charge, liposome size, and amt. and nature of the charged component (diacyl-PA, diacyl-PG, diacyl-PS, stearylamine (SA), diacyl-TAP) in the liposomes. Both full factorial design and D-optimal designs were created. Several significant main factors and interactions were revealed. Pos. charged liposomes were shown to be toxic. The toxicity of neg. charged liposomes was relatively low. Diacyl-TAP was less toxic than SA, and DPPC was less toxic than DMPC. Low level of pos. charged component was favorable and essential when using egg-PC as the main lipid. The amt. of neg. charged component, the liposome size, and the total lipid concn. did not affect the toxicity within the exptl. room. DPPC appeared to be a good candidate when formulating both pos. and neg. charged liposomes with low cellular toxicity. The concept of statistical exptl. design and multivariate evaluation was shown to be a useful approach in cell toxicity screening studies.
- 26Dokka, S.; Toledo, D.; Shi, X. G.; Castranova, V.; Rojanasakul, Y. Oxygen radical-mediated pulmonary toxicity induced by some cationic liposomes. Pharm. Res. 2000, 17 (5), 521– 525, DOI: 10.1023/A:1007504613351Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXksVGqtbc%253D&md5=136d087f5e3b709d42ddb2dbd430a7cfOxygen radical-mediated pulmonary toxicity induced by some cationic liposomesDokka, Sujatha; Toledo, David; Shi, Xianglin; Castranova, Vincent; Rojanasakul, YonPharmaceutical Research (2000), 17 (5), 521-525CODEN: PHREEB; ISSN:0724-8741. (Kluwer Academic/Plenum Publishers)The objectives of this study are to investigate the toxicity assocd. with polycationic liposomes and to elucidate the underlying mechanism. We tested the hypothesis that the pos. charge of liposomes is a key determinant of toxicity by testing differently charged liposomes in mice. Differently charged liposomal systems including cationic liposomes, LipofectAMINE and DOTAP, and neutral and neg. liposomes were evaluated for their toxicity after pulmonary administration in mice. LDH assay and differential cell counts were performed to measure toxicity and pulmonary inflammation, resp. Reactive oxygen intermediates (ROI) were assessed by chemiluminescence. Instillation of cationic liposomes elicited dose-dependent toxicity and pulmonary inflammation. This effect was more pronounced with the multivalent cationic liposome LipofectAMINE as compared to the monovalent cationic DOTAP. Neutral and neg. liposomes did not exhibit lung toxicity. Toxicity assocd. with cationic liposomes correlated with the oxidative burst induced by the liposomes. LipofectAMINE induced a dose-dependent increase in ROI generation. This effect was less pronounced with DOTAP and absent with neutral and neg. liposomes. ROI play a key role in cationic lipid-mediated toxicity. Polyvalent cationic liposomes cause a release of ROI which are responsible for the pulmonary toxicity.
- 27Sudimack, J. J.; Guo, W.; Tjarks, W.; Lee, R. J. A novel pH-sensitive liposome formulation containing oleyl alcohol. Biochim. Biophys. Acta, Biomembr. 2002, 1564 (1), 31– 7, DOI: 10.1016/S0005-2736(02)00399-1Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XkvFGkt7s%253D&md5=d9666d3a28962812843290d7827b8b4eA novel pH-sensitive liposome formulation containing oleyl alcoholSudimack, Jennifer J.; Guo, Wenjin; Tjarks, Werner; Lee, Robert J.Biochimica et Biophysica Acta, Biomembranes (2002), 1564 (1), 31-37CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)PH-sensitive liposomes are designed to undergo acid-triggered destabilization. First generation pH-sensitive liposomes, based on the cone-shaped lipid dioleoylphosphatidylethanolamine (DOPE), have been shown to lose fusogenicity in the presence of serum. Here, we report the design and evaluation of novel serum-resistant pH-sensitive liposome formulations that are based on the compn. of egg phosphatidylcholine (PC), cholesteryl hemisuccinate (CHEMS), oleyl alc. (OAlc), and Tween-80 (T-80). When loaded with the fluorescent probe calcein, these liposomes exhibited excellent stability at pH 7.4 and underwent rapid destabilization upon acidification as shown by calcein dequenching and particle size increase. Adjusting the mole percentages of T-80 and OAlc in the formulation could regulate the stability and pH-sensitive properties of these liposomes. Liposomes with a higher T-80 content exhibited greater stability but were less sensitive to acid-induced destabilization. Meanwhile, formulations with a higher OAlc content exhibited greater content release in response to low pH. The pH-triggered liposomal destabilization did not produce membrane fusion according to an octadecylrhodamine B chloride (R18) lipid-mixing assay. Compared to DOPE-based pH-sensitive liposomes, the above formulations showed much better retention of their pH-sensitive properties in the presence of 10% serum. These liposomes were then evaluated for intracellular delivery of entrapped cytosine-β-d-arabinofuranoside (araC) in KB human oral cancer cells, which have elevated folate receptor (FR) expression. The FR, which is amplified in many types of human tumors, has been shown to mediate the internalization of folate-derivatized liposomes into an acidic intracellular compartment. FR-targeted OAlc-based pH-sensitive liposomes, entrapping 200 mM araC, showed ∼17-times greater FR-dependent cytotoxicity in KB cells compared to araC delivered via FR-targeted non-pH-sensitive liposomes. These data indicated that pH-sensitive liposomes based on OAlc, combined with FR-mediated targeting, are promising delivery vehicles for membrane impermeable therapeutic agents.
- 28Mann, E. E.; Wozniak, D. J. Pseudomonas biofilm matrix composition and niche biology. FEMS Microbiol Rev. 2012, 36 (4), 893– 916, DOI: 10.1111/j.1574-6976.2011.00322.xGoogle Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xht1OgsL3E&md5=cbdb3348bfd43f0e6995858f5c621793Pseudomonas biofilm matrix composition and niche biologyMann, Ethan E.; Wozniak, Daniel J.FEMS Microbiology Reviews (2012), 36 (4), 893-916CODEN: FMREE4; ISSN:0168-6445. (Wiley-Blackwell)Review. Biofilms are a predominant form of growth for bacteria in the environment and in the clinic. Crit. for biofilm development are adherence, proliferation, and dispersion phases. Each of these stages includes reinforcement by, or modulation of, the extracellular matrix. Pseudomonas aeruginosa has been a model organism for the study of biofilm formation. Addnl., other Pseudomonas species utilize biofilm formation during plant colonization and environmental persistence. Pseudomonads produce several biofilm matrix mols., including polysaccharides, nucleic acids, and proteins. Accessory matrix components shown to aid biofilm formation and adaptability under varying conditions are also produced by pseudomonads. Adaptation facilitated by biofilm formation allows for selection of genetic variants with unique and distinguishable colony morphol. Examples include rugose small-colony variants and wrinkly spreaders (WS), which over produce Psl/Pel or cellulose, resp., and mucoid bacteria that over produce alginate. The well-documented emergence of these variants suggests that pseudomonads take advantage of matrix-building subpopulations conferring specific benefits for the entire population. This review focuses on various polysaccharides as well as addnl. Pseudomonas biofilm matrix components. Discussions center on structure-function relationships, regulation, and the role of individual matrix mols. in niche biol.
- 29Sorroche, F.; Bogino, P.; Russo, D. M.; Zorreguieta, A.; Nievas, F.; Morales, G. M.; Hirsch, A. M.; Giordano, W. Cell Autoaggregation, Biofilm Formation, and Plant Attachment in a Sinorhizobium meliloti lpsB Mutant. Mol. Plant-Microbe Interact. 2018, 31 (10), 1075– 1082, DOI: 10.1094/MPMI-01-18-0004-RGoogle Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlSmsr3J&md5=5b569b743955926ffa77bc62f75c848bCell autoaggregation, biofilm formation, and plant attachment in a sinorhizobium meliloti lpsb mutantSorroche, Fernando; Bogino, Pablo; Russo, Daniela M.; Zorreguieta, Angeles; Nievas, Florela; Morales, Gustavo M.; Hirsch, Ann M.; Giordano, WalterMolecular Plant-Microbe Interactions (2018), 31 (10), 1075-1082CODEN: MPMIEL; ISSN:0894-0282. (APS Press)Bacterial surface mols. arc crucial for the establishment of a successful rhizobia-legume symbiosis, and, in most bacteria, arc also crit. for adherence properties, surface colonization, and as a barrier for defense. Rhizobial mutants defective in the prodn. of exopolysaccharides (EPSs), lipopolysaccharides (LPSs), or capular polysacchar ides are usually affected in symbiosis with their plant hosts. In the present study, we evaluated the role of the combined effects of LPS and EPS II in cell-to-cell and cell-to-surface interactions in Sinorlli-zohium meliloti by studying planktonic cell autoaggrcgation, biofilm formation, and symbiosis with the host plant Medicago sativa. The lpsB mutant, which has a defective core portion of LPS, exhibited a redn. in biofilm formation on a biotic surfaces as well as altered biofilm architecture compared with the wild-type Rm8530 strain. Atomic force microscopy and confocal laser microscopy revealed an increase in polar cell-to-cell inter actions in the IpsB mutant, which might account for the biofilm deficiency. However. a certain level of biofilm development was obsd. in the lpsB strain compared with the EPS 11-defective mutant strains. Autoaggregation expts. carried out with LPS and EPS mutant strains showed that both polysaccharides have an impact on the cell-to-cell adhesive interactions of planktonic bacteria. Although the IpsB mutation and the loss of EPS prodn. strongly stimulated early :attachment to alfalfa roots, the no. of nodules induced in M. sativa was not increased. Taken together, this work demonstrates that S. meliloti interactions with biotic and abiotic surfaces depend on the interplay between LPS and EPS II.
- 30Coulon, C.; Vinogradov, E.; Filloux, A.; Sadovskaya, I. Chemical analysis of cellular and extracellular carbohydrates of a biofilm-forming strain Pseudomonas aeruginosa PA14. PLoS One 2010, 5 (12), e14220, DOI: 10.1371/journal.pone.0014220Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFGqu7jM&md5=679127e9a16522913c471f6572e66952Chemical analysis of cellular and extracellular carbohydrates of a biofilm-forming strain Pseudomonas aeruginosa PA14Coulon, Charlene; Vinogradov, Evgeny; Filloux, Alain; Sadovskaya, IrinaPLoS One (2010), 5 (12), e14220CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)Pseudomonas aeruginosa is a Gram-neg. bacterium and an opportunistic pathogen that causes persisting life-threatening infections in cystic fibrosis (CF) patients. Biofilm mode of growth facilitates its survival in a variety of environments. Most P. aeruginosa isolates, including the non-mucoid lab. strain PA14, are able to form a thick pellicle, which results in a surface-assocd. biofilm at the air-liq. (A-L) interface in standing liq. cultures. Exopolysaccharides (EPS) are considered as key components in the formation of this biofilm pellicle. In the non-mucoid P. aeruginosa strain PA14, the "scaffolding" polysaccharides of the biofilm matrix, and the mols. responsible for the structural integrity of rigid A-L biofilm have not been identified. Moreover, the role of LPS in this process is unclear, and the chem. structure of the LPS O-antigen of PA14 has not yet been elucidated. Principal Findings: In the present work we carried out a systematic anal. of cellular and extracellular (EC) carbohydrates of P. aeruginosa PA14. The authors also elucidated the chem. structure of the LPS O-antigen by chem. methods and 2-D NMR spectroscopy. It is composed of linear trisaccharide repeating units, identical to those described for P. aeruginosa Lanyi type O:2a,c (Lanyi-Bergman O-serogroup 10a, 10c; IATS serotype 19). Furthermore, an EC O-antigen polysaccharide (EC O-PS) and the glycerol-phosphorylated cyclic β-(1,3)-glucans were identified in the culture supernatant of PA14, grown statically in minimal medium. Finally, the extracellular matrix of the thick biofilm formed at the A-L interface contained, in addn. to eDNA, important quantities (at least ∼20% of dry wt.) of LPS-like material. Thus, the authors characterized the chem. structure of the LPS O-antigen and showed that the O-antigen polysaccharide is an abundant extracellular carbohydrate of PA14. They present evidence that LPS-like material is found as a component of a biofilm matrix of P. aeruginosa.
- 31Schooling, S. R.; Beveridge, T. J. Membrane vesicles: an overlooked component of the matrices of biofilms. J. Bacteriol. 2006, 188 (16), 5945– 57, DOI: 10.1128/JB.00257-06Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XosVehtbo%253D&md5=70bb1a3d1f3b6a58911f3eeca87dbbcfMembrane vesicles: an overlooked component of the matrices of biofilmsSchooling, Sarah R.; Beveridge, Terry J.Journal of Bacteriology (2006), 188 (16), 5945-5957CODEN: JOBAAY; ISSN:0021-9193. (American Society for Microbiology)The matrix helps define the architecture and infrastructure of biofilms and also contributes to their resilient nature. Although many studies continue to define the properties of both gram-pos. and gram-neg. bacterial biofilms, there is still much to learn, esp. about how structural characteristics help bridge the gap between the chem. and phys. aspects of the matrix. Here, we show that membrane vesicles (MVs), structures derived from the outer membrane of gram-neg. bacteria, are a common particulate feature of the matrix of Pseudomonas aeruginosa biofilms. Biofilms grown using different model systems and growth conditions were shown to contain MVs when thin sectioned for TEM, and mech. disrupted biofilms revealed MVs in assocn. with intercellular material. MVs were also isolated from biofilms by employing techniques for matrix isolation and a modified MV isolation protocol. Together these observations verified the presence and frequency of MVs and indicated that MVs were a definite component of the matrix. Characterization of planktonic and biofilm-derived MVs revealed quant. and qual. differences between the two and indicated functional roles, such as proteolytic activity and binding of antibiotics. The ubiquity of MVs was supported by observations of biofilms from a variety of natural environments outside the lab. and established MVs as common biofilm constituents. MVs appear to be important and relatively unacknowledged particulate components of the matrix of gram-neg. or mixed bacterial biofilms.
- 32Jabbouri, S.; Sadovskaya, I. Characteristics of the biofilm matrix and its role as a possible target for the detection and eradication of Staphylococcus epidermidis associated with medical implant infections. FEMS Immunol. Med. Microbiol. 2010, 59 (3), 280– 91, DOI: 10.1111/j.1574-695X.2010.00695.xGoogle Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtVeju77I&md5=c928c7c90bbd5a7ecbe48174b09d8855Characteristics of the biofilm matrix and its role as a possible target for the detection and eradication of Staphylococcus epidermidis associated with medical implant infectionsJabbouri, Said; Sadovskaya, IrinaFEMS Immunology and Medical Microbiology (2010), 59 (3), 280-291CODEN: FIMIEV; ISSN:0928-8244. (Wiley-Blackwell)The virulence of Staphylococcus epidermidis is related to its capacity to form biofilms. Such biofilm-related infections are extremely difficult to treat and to detect in early stages by the traditional microbiol. analyses. The detn. of the chem. compn. of the extracellular polymeric substances (EPS) of the biofilm matrix, as well as the elucidation of the sensitivity of biofilms to enzymic degrdn. should facilitate the development of new therapies against biofilm-related infections. The chem. analyses of EPS had shown qual. and quant. variations of their nature, depending on the strains and culture conditions. The poly-N-acetylglucosamine (PNAG) is considered the main component of staphylococcal biofilms. However, certain strains form biofilms without PNAG. In addn. to PNAG and proteins, extracellular teichoic acid was identified as a new component of the staphylococcal biofilms. The sensitivity of staphylococcal biofilms to enzymic treatments depended on their relative chem. compn., and a PNAG-degrading enzyme, in conjunction with proteases, could be an efficient soln. to eliminate the staphylococcal biofilms. A detection of specific 'antibiofilm' antibodies in the blood serum of patients could serve as a convenient noninvasive and inexpensive diagnostic tool for the detection of foreign body-assocd. staphylococcal infections. Used as a coating antigen in the ELISA test, PNAG did not sufficiently discriminate healthy individuals from the infected patients.
- 33Sadovskaya, I.; Chaignon, P.; Kogan, G.; Chokr, A.; Vinogradov, E.; Jabbouri, S. Carbohydrate-containing components of biofilms produced in vitro by some staphylococcal strains related to orthopaedic prosthesis infections. FEMS Immunol. Med. Microbiol. 2006, 47 (1), 75– 82, DOI: 10.1111/j.1574-695X.2006.00068.xGoogle Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlsFWhsLY%253D&md5=8f85249e24039bdb87ff47ed6548d892Carbohydrate-containing components of biofilms produced in vitro by some staphylococcal strains related to orthopedic prosthesis infectionsSadovskaya, Irina; Chaignon, Philippe; Kogan, Grigorij; Chokr, Ali; Vinogradov, Evgeny; Jabbouri, SaidFEMS Immunology and Medical Microbiology (2006), 47 (1), 75-82CODEN: FIMIEV; ISSN:0928-8244. (Blackwell Publishing Ltd.)The capacity of coagulase-neg. staphylococci to colonize implanted medical devices is generally attributed to their ability to produce biofilms. Biofilm of the model strain of Staphylococcus epidermidis RP62A was shown to contain two carbohydrate-contg. moieties, a linear poly-β-(1 → 6)-N-acetyl-D-glucosamine (PNAG) and teichoic acid. In the present study, the authors investigated several biofilm-producing staphylococci isolated from infected orthopedic implants and characterized the compn. of the lab.-grown biofilms using chem. anal. and 1H NMR spectroscopy. Extracellular teichoic acid was produced by all strains studied. Some of the clin. strains were shown to produce biofilms with compns. similar to that of the model strain, contg. a varying amt. of PNAG. The chem. structure of PNAG of the clin. strains was similar to that previously described for the model strains S. epidermidis RP62A and Staphylococcus aureus MN8m, differing only in the amt. of charged groups. Biofilms of the strains producing a substantial amt. of PNAG were detached by dispersin B, a PNAG-degrading enzyme, while being unsusceptible to proteinase K treatment. On the other hand, some strains produced biofilms without any detectable amt. of PNAG. The biofilms of these strains were dispersed by proteinase K, but not by dispersin B.
- 34Kogan, G.; Sadovskaya, I.; Chaignon, P.; Chokr, A.; Jabbouri, S. Biofilms of clinical strains of Staphylococcus that do not contain polysaccharide intercellular adhesin. FEMS Microbiol. Lett. 2006, 255 (1), 11– 6, DOI: 10.1111/j.1574-6968.2005.00043.xGoogle Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjsVyrtbo%253D&md5=703e008c2fd50868538ea45d8289cd01Biofilms of clinical strains of Staphylococcus that do not contain polysaccharide intercellular adhesinKogan, Grigorij; Sadovskaya, Irina; Chaignon, Philippe; Chokr, Ali; Jabbouri, SaidFEMS Microbiology Letters (2006), 255 (1), 11-16CODEN: FMLED7; ISSN:0378-1097. (Blackwell Publishing Ltd.)Staphylococcus aureus and coagulase-neg. staphylococci, primarily Staphylococcus epidermidis, are recognized as a major cause of nosocomial infections assocd. with the use of implanted medical devices. The capacity of S. epidermidis to form biofilms, allowing it to evade host immune defense mechanisms and antibiotic therapy, is considered to be crucial in colonizing the surfaces of medical implants and dissemination of infection. It has previously been demonstrated that the biofilm of a model strain S. epidermidis RP62A comprises two carbohydrate-contg. moieties, a polysaccharide having a structure of a linear poly-N-acetyl-(1 → 6)-β-D-glucosamine and teichoic acid. Here, the authors show that, unlike this model strain, certain clin. isolates of coagulase-neg. staphylococci produce biofilms that do not contain detectable amts. of poly-N-acetyl-(1 → 6)-β-D-glucosamine. In contrast to that of S. epidermidis RP62A, these biofilms are not detached with metaperiodate, while proteinase K causes their partial dispersal.
- 35Warshakoon, H. J.; Burns, M. R.; David, S. A. Structure-activity relationships of antimicrobial and lipoteichoic acid-sequestering properties in polyamine sulfonamides. Antimicrob. Agents Chemother. 2009, 53 (1), 57– 62, DOI: 10.1128/AAC.00812-08Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1Kksr0%253D&md5=d103ce5456e8b391e1bacf3df8c98849Structure-activity relationships of antimicrobial and lipoteichoic acid-sequestering properties in polyamine sulfonamidesWarshakoon, Hemamali J.; Burns, Mark R.; David, Sunil A.Antimicrobial Agents and Chemotherapy (2009), 53 (1), 57-62CODEN: AMACCQ; ISSN:0066-4804. (American Society for Microbiology)We have recently confirmed that lipoteichoic acid (LTA), a major constituent of the gram-pos. bacterial surface, is the endotoxin of gram-pos. bacteria that induces proinflammatory mols. in a Toll-like receptor 2 (TLR2)-dependent manner. LTA is an anionic amphipath whose physicochem. properties are similar to those of lipopolysaccharide (LPS), which is found on the outer leaflet of the outer membranes of gram-neg. organisms. Hypothesizing that compds. that sequester LPS could also bind to and inhibit LTA-induced cellular activation, we screened congeneric series of polyamine sulfonamides which we had previously shown effectively neutralized LPS both in vitro and in animal models of endotoxemia. We obsd. that these compds. do bind to and neutralize LTA, as reflected by the inhibition of TLR2-mediated NF-κB induction in reporter gene assays. Structure-activity studies showed a clear dependence of the acyl chain length on activity against LTA in compds. with spermine and homospermine scaffolds. We then sought to examine possible correlations between the neutralizing potency toward LTA and antimicrobial activity in Staphylococcus aureus. A linear relationship between LTA sequestration activity and antimicrobial activity for compds. with a spermine backbone was obsd., while all compds. with a homospermine backbone were equally active against S. aureus, regardless of their neutralizing potency toward LTA. These results suggest that the no. of protonatable charges is a key determinant of the activity toward the membranes of gram-pos. bacteria. The development of resistance to membrane-active antibiotics has been relatively slower than that to conventional antibiotics, and it is possible that compds. such as the acylpolyamines may be useful clin., provided that they have an acceptable safety profile and margin of safety. A more detailed understanding of the mechanisms of interactions of these compds. with LPS and LTA, as well as the gram-neg. and -pos. bacterial cell surfaces, will be instructive and should allow the rational design of analogs which combine antisepsis and antibacterial properties.
- 36Swoboda, J. G.; Campbell, J.; Meredith, T. C.; Walker, S. Wall teichoic acid function, biosynthesis, and inhibition. ChemBioChem 2010, 11 (1), 35– 45, DOI: 10.1002/cbic.200900557Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1SqtLrE&md5=050008f52b07198ece482cccdf237b4fWall teichoic acid function, biosynthesis, and inhibitionSwoboda, Jonathan G.; Campbell, Jennifer; Meredith, Timothy C.; Walker, SuzanneChemBioChem (2010), 11 (1), 35-45CODEN: CBCHFX; ISSN:1439-4227. (Wiley-VCH Verlag GmbH & Co. KGaA)A review.
- 37Neuhaus, F. C.; Baddiley, J. A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteria. Microbiol. Mol. Biol. Rev. 2003, 67 (4), 686– 723, DOI: 10.1128/MMBR.67.4.686-723.2003Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmt1SqsA%253D%253D&md5=e47cfc2263faafd6fc8fd7a6671acf72A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteriaNeuhaus, Francis C.; Baddiley, JamesMicrobiology and Molecular Biology Reviews (2003), 67 (4), 686-723CODEN: MMBRF7; ISSN:1092-2172. (American Society for Microbiology)A review. Teichoic acids (TAs) are major wall and membrane components of most gram-pos. bacteria. With few exceptions, they are polymers of glycerol-phosphate or ribitol-phosphate to which are attached glycosyl and D-alanyl ester residues. Wall TA is attached to peptidoglycan via a linkage unit, whereas lipoteichoic acid is attached to glycolipid intercalated in the membrane. Together with peptidoglycan, these polymers make up a polyanionic matrix that functions in (1) cation homeostasis; (2) trafficking of ions, nutrients, proteins, and antibiotics; (3) regulation of autolysins; and (4) presentation of envelope proteins. The esterification of TAs with D-alanyl esters provides a means of modulating the net anionic charge, detg. the cationic binding capacity, and displaying cations in the wall. This review addresses the structures and functions of D-alanyl-TAs, the D-alanylation system encoded by the dlt operon, and the roles of TAs in cell growth. The importance of dlt in the physiol. of many organisms is illustrated by the variety of mutant phenotypes. In addn., advances in our understanding of D-alanyl ester function in virulence and host-mediated responses have been made possible through targeted mutagenesis of dlt. Studies of the mechanism of D-alanylation have identified two potential targets of antibacterial action and provided possible screening reactions for designing novel agents targeted to D-alanyl-TA synthesis.
- 38Martinic, M.; Hoare, A.; Contreras, I.; Alvarez, S. A. Contribution of the lipopolysaccharide to resistance of Shigella flexneri 2a to extreme acidity. PLoS One 2011, 6 (10), e25557, DOI: 10.1371/journal.pone.0025557Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlGmtL3I&md5=1c259a1c0872e2a7867a619599bd62faContribution of the lipopolysaccharide to resistance of Shigella flexneri 2a to extreme acidityMartinic, Mara; Hoare, Anilei; Contreras, Ines; Alvarez, Sergio A.PLoS One (2011), 6 (10), e25557CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)Shigella flexneri is endemic in most underdeveloped countries, causing diarrheal disease and dysentery among young children. In order to reach its target site, the colon, Shigella must overcome the acid environment of the stomach. Shigella is able to persist in this stressful environment and, because of this ability it can initiate infection following the ingestion of very small inocula. Thus, acid resistance is considered an important virulence trait of this bacterium. It was reported that moderate acid conditions regulate the expression of numerous components of the bacterial envelope. Because the lipopolysaccharide (LPS) is the major component of the bacterial surface, here we have addressed the role of LPS in acid resistance of S. flexneri 2a. Defined deletion mutants in genes encoding proteins involved in the synthesis, assembly and length regulation of the LPS O antigen were constructed and assayed for resistance to pH 2.5 after adaptation to pH 5.5. The results showed that a mutant lacking O antigen was significantly more sensitive to extreme acid conditions than the wild type. Not only the presence of polymd. O antigen, but also a particular polymer length (S-OAg) was required for acid resistance. Glucosylation of the O antigen also contributed to this property. In addn., a moderate acidic pH induced changes in the compn. of the lipid A domain of LPS. The main modification was the addn. of phosphoethanolamine to the 1' phosphate of lipid A. This modification increased resistance of S. flexneri to extreme acid conditions, provide that O antigen was produced. Overall, the results of this work point out to an important role of LPS in resistance of Shigella flexneri to acid stress.
- 39Brade, H.; Galanos, C. Isolation, purification, and chemical analysis of the lipopolysaccharide and lipid A of Acinetobacter calcoaceticus NCTC 10305. Eur. J. Biochem. 1982, 122 (2), 233– 7, DOI: 10.1111/j.1432-1033.1982.tb05871.xGoogle Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL38XpvFOgtQ%253D%253D&md5=b6ed534a884e06e334f0a6caff38a56fIsolation, purification, and chemical analysis of the lipopolysaccharide and lipid A of Acinetobacter calcoaceticus NCTC 10305Brade, Helmut; Galanos, ChrisEuropean Journal of Biochemistry (1982), 122 (2), 233-7CODEN: EJBCAI; ISSN:0014-2956.The lipopolysaccharide of A. calcoaceticus NCTC 10305 was obtained by a modified PhOH/CHCl3/light petroleum method from the bacterial cells and from the culture medium in yields of 1.6% and 2.2%, resp. (based on the bacterial dry wt.). On chem. anal., the prepns. proved to be identical. The lipopolysaccharide obtained from the cells was purified by repeated ultracentrifugation, electrodialysis, and pptn. with NaCl. It was free of nucleic acids, proteins, and glycans. In the anal. ultracentrifuge, the triethylamine and Na salt forms of the lipopolysaccharide showed a sedimentation coeff. of 8.9 S and 51 S, resp. The lipopolysaccharide consisted of glucosamine, 3-deoxy-D-manno-octulosonic acid, D-glucose, fatty acids, and phosphate in a molar ratio of 2:1:7:6:4. The fatty acids were predominantly lauric acid, 2-hydroxy, and 3-hydroxylauric acid in a molar ratio of 1:1:2. Only 3-hydroxylauric acid was found in amide linkage. On mild acid hydrolysis of the lipopolysaccharide, 65% lipid A were obtained, to which glucosamine was retained quant. It still contained 50% of the original glucose, whereas 1/3 of the liberated glucose was in monomeric form.
- 40Sutherland, I. Biofilm exopolysaccharides: a strong and sticky framework. Microbiology (London, U. K.) 2001, 147 (1), 3– 9, DOI: 10.1099/00221287-147-1-3Google ScholarThere is no corresponding record for this reference.
- 41Duanis-Assaf, D.; Duanis-Assaf, T.; Zeng, G.; Meyer, R. L.; Reches, M.; Steinberg, D.; Shemesh, M. Cell wall associated protein TasA provides an initial binding component to extracellular polysaccharides in dual-species biofilm. Sci. Rep. 2018, 8 (1), 9350, DOI: 10.1038/s41598-018-27548-1Google Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1Mbpt1Kiuw%253D%253D&md5=aceb4fc30d8b3b8aedcd956f8b8c2b14Cell wall associated protein TasA provides an initial binding component to extracellular polysaccharides in dual-species biofilmDuanis-Assaf Danielle; Shemesh Moshe; Duanis-Assaf Danielle; Steinberg Doron; Duanis-Assaf Tal; Reches Meital; Zeng Guanghong; Meyer Rikke LouiseScientific reports (2018), 8 (1), 9350 ISSN:.Many bacteria in biofilm surround themselves by an extracellular matrix composed mainly of extracellular polysaccharide (EP), proteins such as amyloid-like fibers (ALF) and nucleic acids. While the importance of EP in attachment and acceleration of biofilm by a number of different bacterial species is well established, the contribution of ALF to attachment in multispecies biofilm remains unknown. The study presented here aimed to investigate the role of TasA, a precursor for ALF, in cell-cell interactions in dual-species biofilms of Bacillus subtilis and Streptococcus mutans. Expression of major B. subtilis matrix operons was significantly up-regulated in the presence of S. mutans during different stages of biofilm formation, suggesting that the two species interacted and modulated gene expression in each other. Wild-type B. subtilis expressing TasA adhered strongly to S. mutans biofilm, while a TasA-deficient mutant was less adhesive and consequently less abundant in the dual-species biofilm. Dextran, a biofilm polysaccharide, induced aggregation of B. subtilis and stimulated adhesion to S. mutans biofilms. This effect was only observed in the wild-type strain, suggesting that interactions between TasA and dextran-associated EP plays an important role in inter-species interactions during initial stages of multispecies biofilm development.
- 42Chandra, P.; Enespa; Singh, R.; Arora, P. K. Microbial lipases and their industrial applications: a comprehensive review. Microb. Cell Fact. 2020, 19, 169, DOI: 10.1186/s12934-020-01428-8Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhs1ygt7nL&md5=c0e49e9ac0a09ec8ab62bcc34200b932Microbial lipases and their industrial applications: a comprehensive reviewChandra, Prem; Enespa; Singh, Ranjan; Arora, Pankaj KumarMicrobial Cell Factories (2020), 19 (1), 169CODEN: MCFICT; ISSN:1475-2859. (BioMed Central Ltd.)A review. Lipases are very versatile enzymes, and produced the attention of the several industrial processes. Lipase can be achieved from several sources, animal, vegetable, and microbiol. The uses of microbial lipase market is estd. to be USD 425.0 Million in 2018 and it is projected to reach USD 590.2 Million by 2023, growing at a CAGR of 6.8% from 2018. Microbial lipases (EC 3.1.1.3) catalyze the hydrolysis of long chain triglycerides. The microbial origins of lipase enzymes are logically dynamic and proficient also have an extensive range of industrial uses with the manufg. of altered mols. The unique lipase (triacylglycerol acyl hydrolase) enzymes catalyzed the hydrolysis, esterification and alcoholysis reactions. Immobilization has made the use of microbial lipases accomplish its best performance and hence suitable for several reactions and need to enhance aroma to the immobilization processes. Immobilized enzymes depend on the immobilization technique and the carrier type. The choice of the carrier concerns usually the biocompatibility, chem. and thermal stability, and insoly. under reaction conditions, capability of easy rejuvenation and reusability, as well as cost proficiency. Bacillus spp., Achromobacter spp., Alcaligenes spp., Arthrobacter spp., Pseudomonos spp., of bacteria and Penicillium spp., Fusarium spp., Aspergillus spp., of fungi are screened large scale for lipase prodn. Lipases as multipurpose biol. catalyst has given a favorable vision in meeting the needs for several industries such as biodiesel, foods and drinks, leather, textile, detergents, pharmaceuticals and medicals. This review represents a discussion on microbial sources of lipases, immobilization methods increased productivity at market profitability and reduce logistical liability on the environment and user.
- 43Dully, M.; Brasnett, C.; Djeghader, A.; Seddon, A.; Neilan, J.; Murray, D.; Butler, J.; Soulimane, T.; Hudson, S. P. Modulating the release of pharmaceuticals from lipid cubic phases using a lipase inhibitor. J. Colloid Interface Sci. 2020, 573, 176– 192, DOI: 10.1016/j.jcis.2020.04.015Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXmvVSntL4%253D&md5=0e5a45b15dc805d4cf579b6b7b6258eeModulating the release of pharmaceuticals from lipid cubic phases using a lipase inhibitorDully, Michele; Brasnett, Christopher; Djeghader, Ahmed; Seddon, Annela; Neilan, John; Murray, David; Butler, James; Soulimane, Tewfik; Hudson, Sarah P.Journal of Colloid and Interface Science (2020), 573 (), 176-192CODEN: JCISA5; ISSN:0021-9797. (Elsevier B.V.)Lipid cubic phase formulations have gained recognition as potential controlled delivery systems for a range of active pharmaceutical and biol. agents on account of their desirable physiochem. properties and ability to encapsulate both hydrophobic and hydrophilic mols. The most widely studied lipid cubic systems are those of the monoacylglycerol lipid family. These formulations are susceptible to lipolysis by a variety of enzymes, including lipases and esterases, which attack the ester bond present on the lipid chain bridging the oleic acid component to the glycerol backbone. The release of poorly sol. mols. residing in the lipid membrane portions of the phase is limited by the breakdown of the matrix; thus, presenting a potential means for further controlling and sustaining the release of therapeutic agents by targeting the matrix stability and its rate of degrdn. The aims of the present study were twofold: to evaluate an approach to regulate the rate of degrdn. of lipid cubic phase drug delivery systems by targeting the enzyme interactions responsible for their demise; and to study the subsequent drug release profiles from bulk lipid cubic gels using model drugs of contrasting hydrophobicity. Here, hybrid materials consisting of cubic phases with monoacylglycerol lipids of different chain lengths formulated with a potent lipase inhibitor tetrahydrolipstatin were designed. Modulation of the release of a hydrophobic model pharmaceutical, a clofazimine salt, was obtained by exploiting the matrixes' enzyme-driven digestion. A stable cubic phase is described, displaying controlled degrdn. with at least a 4-fold improvement compared to the blank systems shown in inhibitor-contg. cubic systems. Sustained release of the model hydrophobic pharmaceutical was studied over 30 days to highlight the advantage of incorporating an inhibitor into the cubic network to achieve tunable lipid release systems. This is done without neg. affecting the structure of the matrix itself, as shown by comprehensive small-angle x-ray scattering expts.
- 44Chen, M.; Wei, J.; Xie, S.; Tao, X.; Zhang, Z.; Ran, P.; Li, X. Bacterial biofilm destruction by size/surface charge-adaptive micelles. Nanoscale 2019, 11 (3), 1410– 1422, DOI: 10.1039/C8NR05575KGoogle Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisFyntbvI&md5=64da4f386aca2e3dd667dbe1eac85e1dBacterial biofilm destruction by size/surface charge-adaptive micellesChen, Maohua; Wei, Jiaojun; Xie, Songzhi; Tao, Xinyan; Zhang, Zhanlin; Ran, Pan; Li, XiaohongNanoscale (2019), 11 (3), 1410-1422CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Biofilms formed by pathogenic bacteria are one of the most important reasons for multidrug resistance. One of the major limitations in the biofilm treatment is the existence of intensive matrixes, which greatly block the diffusion of antimicrobial agents. In the current study, we designed poly(aspartamide)-derived micelles self-assembled from cationic copolymers with azithromycin-conjugated and pH-sensitive copolymers, followed by loading cis-aconityl-D-tyrosine (CA-Tyr) via electrostatic interactions. In response to the acidic microenvironment of the biofilm matrix, the hydrophilic transition of the pH-sensitive copolymers and the removal of CA-Tyr led to a sharp decrease in micelle size from 107 nm to 54 nm and a rapid shift in their zeta potential from -11.7 mV to +26.4 mV, which facilitated the penetration of the micelles into biofilms. The acid-labile release of D-tyrosine disintegrated the biofilm matrix, and the lipase-triggered release of azithromycin eradicated the bacteria in the biofilms. An in vitro test was performed on pre-established P. aeruginosa biofilms in microwells, while biofilms grown on catheters were surgically implanted in rats for in vivo evaluation. The results demonstrated the capabilities of the size/surface charge-adaptive micelles in the intensive infiltration in the biofilm matrix and spatiotemporal release of biofilm dispersion and antibacterial agents for the comprehensive treatment of biofilm-relevant infections.
- 45do Vale, A.; Cabanes, D.; Sousa, S. Bacterial Toxins as Pathogen Weapons Against Phagocytes. Front. Microbiol. 2016, 7, 42, DOI: 10.3389/fmicb.2016.00042Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28jgt1ajug%253D%253D&md5=df73510cd5384092bc8537e89cf8d860Bacterial Toxins as Pathogen Weapons Against Phagocytesdo Vale Ana; Cabanes Didier; Sousa SandraFrontiers in microbiology (2016), 7 (), 42 ISSN:1664-302X.Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favor microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signaling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.
- 46Seilie, E. S.; Bubeck Wardenburg, J. Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity. Semin. Cell Dev. Biol. 2017, 72, 101– 116, DOI: 10.1016/j.semcdb.2017.04.003Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXnt1CqsL4%253D&md5=6441357949f86fdad33c76e1a37f13d4Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexitySeilie, E. Sachiko; Bubeck Wardenburg, JulianeSeminars in Cell & Developmental Biology (2017), 72 (), 101-116CODEN: SCDBFX; ISSN:1084-9521. (Elsevier Ltd.)A review. Staphylococcus aureus is a prominent human pathogen capable of infecting a variety of host species and tissue sites. This versatility stems from the pathogen's ability to secrete diverse host-damaging virulence factors. Among these factors, the S. aureus pore-forming toxins (PFTs) α-toxin and the bicomponent leukocidins, have garnered much attention for their ability to lyse cells at low concns. and modulate disease severity. Although many of these toxins were discovered nearly a century ago, their host cell specificities have only been elucidated over the past five to six years, starting with the discovery of the eukaryotic receptor for α-toxin and rapidly followed by identification of the leukocidin receptors. The identification of these receptors has revealed the species- and cell type-specificity of toxin binding, and provided insight into non-lytic effects of PFT intoxication that contribute to disease pathogenesis.
- 47Kennedy, A. D.; Wardenburg, J. B.; Gardner, D. J.; Long, D.; Whitney, A. R.; Braughton, K. R.; Schneewind, O.; DeLeo, F. R. Targeting of alpha-hemolysin by active or passive immunization decreases severity of USA300 skin infection in a mouse model. J. Infect. Dis. 2010, 202 (7), 1050– 1058, DOI: 10.1086/656043Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3cjosVyktQ%253D%253D&md5=00c95ac9cdb4554b6ec183edd1d4a2cbTargeting of alpha-hemolysin by active or passive immunization decreases severity of USA300 skin infection in a mouse modelKennedy Adam D; Bubeck Wardenburg Juliane; Gardner Donald J; Long Daniel; Whitney Adeline R; Braughton Kevin R; Schneewind Olaf; DeLeo Frank RThe Journal of infectious diseases (2010), 202 (7), 1050-8 ISSN:.Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are predominantly those affecting skin and soft tissues. Although progress has been made, our knowledge of the molecules that contribute to the pathogenesis of CA-MRSA skin infections is incomplete. We tested the hypothesis that alpha-hemolysin (Hla) contributes to the severity of USA300 skin infections in mice and determined whether vaccination against Hla reduces disease severity. Isogenic hla-negative (Deltahla) strains caused skin lesions in a mouse infection model that were significantly smaller than those caused by wild-type USA300 and Newman strains. Moreover, infection due to wild-type strains produced dermonecrotic skin lesions, whereas there was little or no dermonecrosis in mice infected with Deltahla strains. Passive immunization with Hla-specific antisera or active immunization with a nontoxigenic form of Hla significantly reduced the size of skin lesions caused by USA300 and prevented dermonecrosis. We conclude that Hla is a potential target for therapeutics or vaccines designed to moderate severe S. aureus skin infections.
- 48Fang, R. H.; Luk, B. T.; Hu, C. M.; Zhang, L. Engineered nanoparticles mimicking cell membranes for toxin neutralization. Adv. Drug Delivery Rev. 2015, 90, 69– 80, DOI: 10.1016/j.addr.2015.04.001Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXms1Wqs7k%253D&md5=3e5830a5084e6e23f503ebbad29db975Engineered nanoparticles mimicking cell membranes for toxin neutralizationFang, Ronnie H.; Luk, Brian T.; Hu, Che-Ming J.; Zhang, LiangfangAdvanced Drug Delivery Reviews (2015), 90 (), 69-80CODEN: ADDREP; ISSN:0169-409X. (Elsevier B.V.)Protein toxins secreted from pathogenic bacteria and venomous animals rely on multiple mechanisms to overcome the cell membrane barrier to inflict their virulence effect. A promising therapeutic concept toward developing a broadly applicable anti-toxin platform is to administer cell membrane mimics as decoys to sequester these virulence factors. As such, lipid membrane-based nanoparticulates are an ideal candidate given their structural similarity to cellular membranes. This article reviews the virulence mechanisms employed by toxins at the cell membrane interface and highlights the application of cell-membrane mimicking nanoparticles as toxin decoys for systemic detoxification. In addn., the implication of particle/toxin nanocomplexes in the development of toxoid vaccines is discussed.
- 49Vandenesch, F.; Lina, G.; Henry, T. Staphylococcus aureus hemolysins, bi-component leukocidins, and cytolytic peptides: a redundant arsenal of membrane-damaging virulence factors?. Front. Cell. Infect. Microbiol. 2012, 2, 12, DOI: 10.3389/fcimb.2012.00012Google Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38bgvF2gsQ%253D%253D&md5=7ad8a181cfcf882127f26514b7d492c2Staphylococcus aureus hemolysins, bi-component leukocidins, and cytolytic peptides: a redundant arsenal of membrane-damaging virulence factors?Vandenesch Francois; Lina G; Henry ThomasFrontiers in cellular and infection microbiology (2012), 2 (), 12 ISSN:.One key aspect of the virulence of Staphylococcus aureus lies in its ability to target the host cell membrane with a large number of membrane-damaging toxins and peptides. In this review, we describe the hemolysins, the bi-component leukocidins (which include the Panton Valentine leukocidin, LukAB/GH, and LukED), and the cytolytic peptides (phenol soluble modulins). While at first glance, all of these factors might appear redundant, it is now clear that some of these factors play specific roles in certain S. aureus life stages and diseases or target specific cell types or species. In this review, we present an update of the literature on toxin receptors and their cell type and species specificities. Furthermore, we review epidemiological studies and animal models illustrating the role of these membrane-damaging factors in various diseases. Finally, we emphasize the interplay of these factors with the host immune system and highlight all their non-lytic functions.
- 50Perera, R. T.; Fleming, A. M.; Peterson, A. M.; Heemstra, J. M.; Burrows, C. J.; White, H. S. Unzipping of A-Form DNA-RNA, A-Form DNA-PNA, and B-Form DNA-DNA in the alpha-Hemolysin Nanopore. Biophys. J. 2016, 110 (2), 306– 314, DOI: 10.1016/j.bpj.2015.11.020Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVeisrnF&md5=a83375c82b0d649d140f24db51ee265bUnzipping of A-Form DNA-RNA, A-Form DNA-PNA, and B-Form DNA-DNA in the α-Hemolysin NanoporePerera, Rukshan T.; Fleming, Aaron M.; Peterson, Amberlyn M.; Heemstra, Jennifer M.; Burrows, Cynthia J.; White, Henry S.Biophysical Journal (2016), 110 (2), 306-314CODEN: BIOJAU; ISSN:0006-3495. (Cell Press)Unzipping of double-stranded nucleic acids by an elec. field applied across a wild-type α-hemolysin (αHL) nanopore provides structural information about different duplex forms. Comparative studies on A-form DNA-RNA duplexes and B-form DNA-DNA duplexes with a single-stranded tail identified significant differences in the blockage current and the unzipping duration between the two helical forms. The B-form duplex blocks the channel 1.9 ± 0.2 pA more and unzips ∼15-fold more slowly than an A-form duplex at 120 mV. The authors developed a model to describe the dependence of duplex unzipping on structure. The wider A-form duplex (d = 2.4 nm) is unable to enter the vestibule opening of αHL on the cis side, leading to unzipping outside of the nanopore with higher residual current and faster unzipping times. In contrast, the smaller B-form duplexes (d = 2.0 nm) enter the vestibule of αHL, resulting in decreased current blockages and slower unzipping. The authors studied the effects of varying the length of the single-stranded overhang, and studied A-form DNA-PNA duplexes to provide addnl. support for the proposed model. This study identifies key differences between A- and B-form duplex unzipping that will be important in the design of future probe-based methods for detecting DNA or RNA.
- 51Sanjay, S. T.; Zhou, W.; Dou, M.; Tavakoli, H.; Ma, L.; Xu, F.; Li, X. Recent advances of controlled drug delivery using microfluidic platforms. Adv. Drug Delivery Rev. 2018, 128, 3– 28, DOI: 10.1016/j.addr.2017.09.013Google Scholar51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1Sqtr3O&md5=64c40e947a71171c4e9630ef3b4e3330Recent advances of controlled drug delivery using microfluidic platformsSanjay, Sharma T.; Zhou, Wan; Dou, Maowei; Tavakoli, Hamed; Ma, Lei; Xu, Feng; Li, XiuJunAdvanced Drug Delivery Reviews (2018), 128 (), 3-28CODEN: ADDREP; ISSN:0169-409X. (Elsevier B.V.)Conventional systematically-administered drugs distribute evenly throughout the body, get degraded and excreted rapidly while crossing many biol. barriers, leaving min. amts. of the drugs at pathol. sites. Controlled drug delivery aims to deliver drugs to the target sites at desired rates and time, thus enhancing the drug efficacy, pharmacokinetics, and bioavailability while maintaining minimal side effects. Due to a no. of unique advantages of the recent microfluidic lab-on-a-chip technol., microfluidic lab-on-a-chip has provided unprecedented opportunities for controlled drug delivery. Drugs can be efficiently delivered to the target sites at desired rates in a well-controlled manner by microfluidic platforms via integration, implantation, localization, automation, and precise control of various microdevice parameters. These features accordingly make reproducible, on-demand, and tunable drug delivery become feasible. On-demand self-tuning dynamic drug delivery systems have shown great potential for personalized drug delivery. This review presents an overview of recent advances in controlled drug delivery using microfluidic platforms. The review first briefly introduces microfabrication techniques of microfluidic platforms, followed by detailed descriptions of numerous microfluidic drug delivery systems that have significantly advanced the field of controlled drug delivery. Those microfluidic systems can be sepd. into four major categories, namely drug carrier-free micro-reservoirbased drug delivery systems, highly integrated carrier-freemicrofluidic lab-on-a-chip systems, drug carrier-integrated microfluidic systems, and microneedles. Microneedles can be further categorized into five different types, i.e. solid, porous, hollow, coated, and biodegradable microneedles, for controlled transdermal drug delivery. At the end, we discuss current limitations and future prospects of microfluidic platforms for controlled drug delivery.
- 52Hurlow, J.; Couch, K.; Laforet, K.; Bolton, L.; Metcalf, D.; Bowler, P. Clinical Biofilms: A Challenging Frontier in Wound Care. Adv. Wound Care (New Rochelle) 2015, 4 (5), 295– 301, DOI: 10.1089/wound.2014.0567Google Scholar52https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1c%252FgsVGlsw%253D%253D&md5=4947b0135968dd623d057517e783b331Clinical Biofilms: A Challenging Frontier in Wound CareHurlow Jennifer; Couch Kara; Laforet Karen; Bolton Laura; Metcalf Daniel; Bowler PhilAdvances in wound care (2015), 4 (5), 295-301 ISSN:2162-1918.Significance: Biofilms have been implicated in a variety of wound complications. Recent Advances: Research has confirmed that biofilms form in wounds of patients experiencing delayed healing and may be a precursor to infection. Critical Issues: Research into the strength of this association is still in its infancy. Is biofilm formation a cause of these complications, a step toward them, or a signal that unresolved factors injuring tissue or delaying healing are setting the stage for biofilm formation, infection, and healing delay? To qualify biofilms for use in informing clinical practice decisions, biofilm characteristics supporting those decisions need standardized definitions and valid evidence that they predict or diagnose healing or infection outcomes. Literature searches of relevant terms reviewed biofilm definitions and validation of their role in predicting and diagnosing delayed wound healing or infection. Future Directions: Further research is needed to provide a rapid accurate technique to identify and characterize biofilms in ways that optimize their validity in diagnosing or screening patient risk of infection or delayed healing and to inform clinical decisions. This research will help validate biofilm's capacity to support wound care clinical practice decisions and establish their importance in guiding clinical practice.
- 53Schwartz, J. A.; Goss, S. G.; Facchin, F.; Avdagic, E.; Lantis, J. C. Surgical debridement alone does not adequately reduce planktonic bioburden in chronic lower extremity wounds. J. Wound Care 2014, 23 (Sup9), S4– S13, DOI: 10.12968/jowc.2014.23.Sup9.S4Google ScholarThere is no corresponding record for this reference.
- 54Kaiser, P.; Wachter, J.; Windbergs, M. Therapy of infected wounds: overcoming clinical challenges by advanced drug delivery systems. Drug Delivery Transl. Res. 2021, 11 (4), 1545– 1567, DOI: 10.1007/s13346-021-00932-7Google Scholar54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXkvVaksLo%253D&md5=1d715c921b4de0774e1923a3ff80ec7eTherapy of infected wounds: overcoming clinical challenges by advanced drug delivery systemsKaiser, Pia; Waechter, Jana; Windbergs, MaikeDrug Delivery and Translational Research (2021), 11 (4), 1545-1567CODEN: DDTRCY; ISSN:2190-3948. (Springer)In recent years, the incidence of infected wounds is steadily increasing, and so is the clin. as well as economic interest in effective therapies. These combine redn. of pathogen load in the wound with general wound management to facilitate the healing process. The success of current therapies is challenged by harsh conditions in the wound microenvironment, chronicity, and biofilm formation, thus impeding adequate concns. of active antimicrobials at the site of infection. Inadequate dosing accuracy of systemically and topically applied antibiotics is prone to promote development of antibiotic resistance, while in the case of antiseptics, cytotoxicity is a major problem. Advanced drug delivery systems have the potential to enable the tailor-made application of antimicrobials to the side of action, resulting in an effective treatment with negligible side effects. This review provides a comprehensive overview of the current state of treatment options for the therapy of infected wounds. In this context, a special focus is set on delivery systems for antimicrobials ranging from semi-solid and liq. formulations over wound dressings to more advanced carriers such as nano-sized particulate systems, vesicular systems, electrospun fibers, and microneedles, which are discussed regarding their potential for effective therapy of wound infections. Further, established and novel models and anal. techniques for preclin. testing are introduced and a future perspective is provided.
- 55Srivastava, G. K.; Alonso-Alonso, M. L.; Fernandez-Bueno, I.; Garcia-Gutierrez, M. T.; Rull, F.; Medina, J.; Coco, R. M.; Pastor, J. C. Comparison between direct contact and extract exposure methods for PFO cytotoxicity evaluation. Sci. Rep. 2018, 8, 1425, DOI: 10.1038/s41598-018-19428-5Google Scholar55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MvjsFGnsw%253D%253D&md5=fa90084693e6d7061183b94cb6b1d8a1Comparison between direct contact and extract exposure methods for PFO cytotoxicity evaluationSrivastava Girish K; Alonso-Alonso Maria L; Fernandez-Bueno Ivan; Garcia-Gutierrez Maria T; Coco Rosa M; Pastor J Carlos; Srivastava Girish K; Fernandez-Bueno Ivan; Pastor J Carlos; Srivastava Girish K; Fernandez-Bueno Ivan; Coco Rosa M; Pastor J Carlos; Garcia-Gutierrez Maria T; Rull Fernando; Medina Jesus; Pastor J CarlosScientific reports (2018), 8 (1), 1425 ISSN:.A series of recent acute blindness cases following non-complicated retinal detachment surgery caused the release of several health alerts in Spain. The blindness was attributed to certain lots of perfluoro-octane (PFO; a volatile and transient medical device). Similar cases have been reported in other countries. This has raised questions regarding the validity of cytotoxicity test methods currently used to certify the safety of PFO lots. The tests were performed according to the International Organization for Standardization (ISO) norms, using the extract dilution method or the indirect contact method as applied to L929 cells, a line derived from mouse fibroblasts. The limitations of those methods have been resolved in this study by proposing a new cytotoxicity test method for volatile substances. The new method requires direct contact of the tested substance with cells that are similar to those exposed to the substance in the clinical setting. This approach includes a few new technical steps that are crucial for detecting cytotoxicity. Our new method detected toxic PFO lots that corresponded to the lots producing clinical blindness, which previous methods failed to detect. The study suggests applying this new method to avoid occurrence of such cases of blindness.
- 56Ternullo, S.; Basnet, P.; Holsaeter, A. M.; Flaten, G. E.; de Weerd, L.; Skalko-Basnet, N. Deformable liposomes for skin therapy with human epidermal growth factor: The effect of liposomal surface charge. Eur. J. Pharm. Sci. 2018, 125, 163– 171, DOI: 10.1016/j.ejps.2018.10.005Google Scholar56https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvV2gsbzI&md5=328c616541ac5184d1cd2948d67b0005Deformable liposomes for skin therapy with human epidermal growth factor: The effect of liposomal surface chargeTernullo, Selenia; Basnet, Purusotam; Holsaeter, Ann Mari; Flaten, Goeril Eide; de Weerd, Louis; Skalko-Basnet, NatasaEuropean Journal of Pharmaceutical Sciences (2018), 125 (), 163-171CODEN: EPSCED; ISSN:0928-0987. (Elsevier B.V.)The topical administration of exogenous human epidermal growth factor (hEGF) is a promising approach for improved chronic wound therapy. To develop therapeutically superior hEGF formulation, we prepd. hEGF-contg. neutral (NDLs), cationic (CDLs) and anionic (ADLs) deformable liposomes (DLs), resp., since it is expected that the liposomal surface charge can affect both the liposomal physicochem. properties, their skin penetration potential and therapeutic efficacy of liposome-assocd. drug. Among the studied DLs, ADLs were found to be most promising for sustained release of hEGF, as assessed in vitro using the polyamide membrane. Ex vivo studies revealed that all DLs were excellent systems for skin therapy with hEGF and no penetration of hEGF through the full thickness human skin was detected. ADLs provided a depot exhibiting the highest hEGF retention onto the human skin surface. ADLs also revealed enhanced mitogenic activities in human fibroblasts compared to both NDLs and CDLs after 48 h treatment. Moreover, hEGF-contg. ADLs significantly enhanced mitogenic activity in fibroblast as compared to activity of hEGF soln. (pos. control). Similar trends were obsd. in human keratinocytes after 24 h of treatment. We proved that the liposomal surface charge affects the therapeutic potential of hEGF-contg. liposomes. hEGF-contg. ADLs can be a promising nanosystem-based formulation for localized therapy of chronic wounds.
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Abstract
Scheme 1
Scheme 1. Schematic Representation of the Zwitterionic Nanoparticles and Their pH Responsiveness. Image Created by The Micro Art IllustrationsFigure 1
Figure 1. Characterization of the zwitterionic nanoparticles using DLS and TEM imaging. (A) Effect of PPM on zeta potential of the blank PDM formulations at different pH conditions. (B) Effect of CHEMS on zeta potential of the blank PDC formulations at different pH conditions. (C) Particle size and PDI measurements of the different antimicrobial nanoparticles. (D) Zeta potential measurements of the different antimicrobial nanoparticles at pH 7.4 (all values based on mean ± SD; n = 3). (E) Morphology of the PD 95/5, PDC 90/5/5, and PDM 90/5/5 formulation (scale bar = 500 nm).
Figure 2
Figure 2. Effect of pH, time, and storage conditions on the nanoparticles. (A) Effect of storage on the size of the different formulations. (B) Effect of storage on the zeta potential of the different formulations. (C) Effect of pH on the size of the different formulations (n = 2). (D) Effect of pH on the zeta potential of the different formulations (n = 2). (E) Size distribution of the PDM 90/5/5 formulation at pH 5.2 over 24 h. (F) Size distribution of the PDC 90/5/5 formulation at pH 5.2 over 24 h.
Figure 3
Figure 3. Effect of biofilm matrix components and extracellular enzymes. (A) Effect of LTA on fluorescence intensity of PDMRhod 90/5/5 at pH 5.5. (B) Effect of Alexa 594 dextran on fluorescence intensity of the PDM 90/5/5 formulation. (C) Effect of lipase on the size of the PDM 90/5/5 formulations. (D) Effect of α-hemolysin on the absorbance peak of ssDNA. (E) Effect of α-hemolysin on the size of vancomycin-loaded DNA nanogel. (F) Effect of pH on S. aureus interaction with the PDM 90/5/5 formulation.
Figure 4
Figure 4. Entrapment efficiency and drug release measurements. (A) Effect of surface modification on the entrapment efficiency of vancomycin (n = 2). (B) In vitro drug release measurements of free vancomycin, PD 95/5 and PDM 90/5/5 at pH 7.4. (C) In vitro drug release measurements of free vancomycin, PDM 90/5/5 in the presence of different concentrations of lipase. Values based on mean ± SD, n = 3.
Figure 5
Figure 5. In vitro antibiofilm efficacy of the PDM 90/5/5 formulations. (A) Effect of the PDM 90/5/5 formulation on biofilm inhibition and crystal violet staining image. Values based on mean ± SD, n = 3. (B) Effect of the PDM 90/5/5 formulation on early stage biofilm eradication and crystal violet staining image. Values based on mean ± SD, n = 3.
Figure 6
Figure 6. In vitro biofilm binding and penetration, biocompatibility, and ex vivo antibiofilm efficacy of the PDM 90/5/5 formulations. (A) CLSM 3D-images of GFP-labeled S. aureus biofilms after exposure PDMRho 90/5/5 (50 μg/mL) for 0, 30, and 120 min. (B) Cytotoxicity of free vancomycin and formulations against HaCaT cells. Values based on mean ± SD, n = 3. (C) Effect of the PDM 90/5/5 formulation on an ex vivo porcine biofilm model. Data presented as mean ± SD (n = 3).
References
This article references 56 other publications.
- 1Karygianni, L.; Ren, Z.; Koo, H.; Thurnheer, T. Biofilm Matrixome: Extracellular Components in Structured Microbial Communities. Trends Microbiol. 2020, 28 (8), 668– 681, DOI: 10.1016/j.tim.2020.03.0161https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnt1Wjsbo%253D&md5=33a8d64b007a1be3d717a9d239181935Biofilm Matrixome: Extracellular Components in Structured Microbial CommunitiesKarygianni, L.; Ren, Z.; Koo, H.; Thurnheer, T.Trends in Microbiology (2020), 28 (8), 668-681CODEN: TRMIEA; ISSN:0966-842X. (Elsevier Ltd.)A review. Biofilms consist of microbial communities embedded in a 3D extracellular matrix. The matrix is composed of a complex array of extracellular polymeric substances (EPS) that contribute to the unique attributes of biofilm lifestyle and virulence. This ensemble of chem. and functionally diverse biomols. is termed the 'matrixome'. The compn. and mechanisms of EPS matrix formation, and its role in biofilm biol., function, and microenvironment are being revealed. This perspective article highlights recent advances about the multifaceted role of the 'matrixome' in the development, phys.-chem. properties, and virulence of biofilms. We emphasize that targeting biofilm-specific conditions such as the matrixome could lead to precise and effective antibiofilm approaches. We also discuss the limited knowledge in the context of polymicrobial biofilms, and the need for more in-depth analyses of the EPS matrix in mixed communities that are assocd. with many human infectious diseases.
- 2Jamal, M.; Ahmad, W.; Andleeb, S.; Jalil, F.; Imran, M.; Nawaz, M. A.; Hussain, T.; Ali, M.; Rafiq, M.; Kamil, M. A. Bacterial biofilm and associated infections. J. Chin. Med. Assoc. 2018, 81 (1), 7– 11, DOI: 10.1016/j.jcma.2017.07.0122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M7hslWitQ%253D%253D&md5=b6b79e67ea81031bed725a3f9e25bd42Bacterial biofilm and associated infectionsJamal Muhsin; Ahmad Wisal; Hussain Tahir; Rafiq Muhammad; Andleeb Saadia; Jalil Fazal; Kamil Muhammad Atif; Imran Muhammad; Nawaz Muhammad Asif; Ali MuhammadJournal of the Chinese Medical Association : JCMA (2018), 81 (1), 7-11 ISSN:.Microscopic entities, microorganisms that drastically affect human health need to be thoroughly investigated. A biofilm is an architectural colony of microorganisms, within a matrix of extracellular polymeric substance that they produce. Biofilm contains microbial cells adherent to one-another and to a static surface (living or non-living). Bacterial biofilms are usually pathogenic in nature and can cause nosocomial infections. The National Institutes of Health (NIH) revealed that among all microbial and chronic infections, 65% and 80%, respectively, are associated with biofilm formation. The process of biofilm formation consists of many steps, starting with attachment to a living or non-living surface that will lead to formation of micro-colony, giving rise to three-dimensional structures and ending up, after maturation, with detachment. During formation of biofilm several species of bacteria communicate with one another, employing quorum sensing. In general, bacterial biofilms show resistance against human immune system, as well as against antibiotics. Health related concerns speak loud due to the biofilm potential to cause diseases, utilizing both device-related and non-device-related infections. In summary, the understanding of bacterial biofilm is important to manage and/or to eradicate biofilm-related diseases. The current review is, therefore, an effort to encompass the current concepts in biofilm formation and its implications in human health and disease.
- 3Sharma, D.; Misba, L.; Khan, A. U. Antibiotics versus biofilm: an emerging battleground in microbial communities. Antimicrob Resist Infect Control 2019, 8, 76, DOI: 10.1186/s13756-019-0533-33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3M7pvFylsw%253D%253D&md5=3bf1bde023c0e69c1b9df9e1b3116504Antibiotics versus biofilm: an emerging battleground in microbial communitiesSharma Divakar; Misba Lama; Khan Asad UAntimicrobial resistance and infection control (2019), 8 (), 76 ISSN:.Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics. It is one of the major causes of infection persistence especially in nosocomial settings through indwelling devices. Quorum sensing plays an important role in regulating the biofilm formation. There are many approaches being used to control infections by suppressing its formation but CRISPR-CAS (gene editing technique) and photo dynamic therapy (PDT) are proposed to be used as therapeutic approaches to subside bacterial biofim infections, especially caused by deadly drug resistant bad bugs.
- 4Duan, Y.; He, K.; Zhang, G.; Hu, J. Photoresponsive Micelles Enabling Codelivery of Nitric Oxide and Formaldehyde for Combinatorial Antibacterial Applications. Biomacromolecules 2021, 22 (5), 2160– 2170, DOI: 10.1021/acs.biomac.1c002514https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXptFCnsL4%253D&md5=66fec25a001cf0b9b50f7bfaf4af943cPhotoresponsive Micelles Enabling Codelivery of Nitric Oxide and Formaldehyde for Combinatorial Antibacterial ApplicationsDuan, Yutian; He, Kewu; Zhang, Guoying; Hu, JinmingBiomacromolecules (2021), 22 (5), 2160-2170CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)It is of particular interest to develop new antibacterial agents with low risk of drug resistance development and low toxicity toward mammalian cells to combat pathogen infections. Although gaseous signaling mols. (GSMs) such as nitric oxide (NO) and formaldehyde (FA) have broad-spectrum antibacterial performance and the low propensity of drug resistance development, many previous studies heavily focused on nanocarriers capable of delivering only one GSM. Herein, we developed a micellar nanoparticle platform that can simultaneously deliver NO and FA under visible light irradn. An amphiphilic diblock copolymer of poly(ethylene oxide)-b-poly(4-((2-nitro-5-(((2-nitrobenzyl)oxy)methoxy)benzyl)(nitroso)amino)benzyl methacrylate) (PEO-b-PNNBM) was successfully synthesized through atom transfer radical polymn. (ATRP). The resulting diblock copolymer self-assembled into micellar nanoparticles without premature NO and FA leakage, whereas they underwent phototriggered disassembly with the corelease of NO and FA. We showed that the NO- and FA-releasing micellar nanoparticles exhibited a combinatorial antibacterial performance, efficiently killing both Gram-neg. (e.g., Escherichia coli) and Gram-pos. (e.g., Staphylococcus aureus) bacteria with low toxicity to mammalian cells and low hemolytic property. This work provides new insights into the development of GSM-based antibacterial agents.
- 5Koo, H.; Allan, R. N.; Howlin, R. P.; Stoodley, P.; Hall-Stoodley, L. Targeting microbial biofilms: current and prospective therapeutic strategies. Nat. Rev. Microbiol. 2017, 15 (12), 740– 755, DOI: 10.1038/nrmicro.2017.995https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFCqtrjP&md5=57c9f42f90e3e281294ffa92beab6bbcTargeting microbial biofilms: current and prospective therapeutic strategiesKoo, Hyun; Allan, Raymond N.; Howlin, Robert P.; Stoodley, Paul; Hall-Stoodley, LuanneNature Reviews Microbiology (2017), 15 (12), 740-755CODEN: NRMACK; ISSN:1740-1526. (Nature Research)A review. Biofilm formation is a key virulence factor for a wide range of microorganisms that cause chronic infections. The multifactorial nature of biofilm development and drug tolerance imposes great challenges for the use of conventional antimicrobials and indicates the need for multi-targeted or combinatorial therapies. In this Review, we focus on current therapeutic strategies and those under development that target vital structural and functional traits of microbial biofilms and drug tolerance mechanisms, including the extracellular matrix and dormant cells. We emphasize strategies that are supported by in vivo or ex vivo studies, highlight emerging biofilm-targeting technologies and provide a rationale for multi-targeted therapies aimed at disrupting the complex biofilm microenvironment.
- 6Khan, J.; Tarar, S. M.; Gul, I.; Nawaz, U.; Arshad, M. Challenges of antibiotic resistance biofilms and potential combating strategies: a review. 3 Biotech 2021, 11 (4), 169, DOI: 10.1007/s13205-021-02707-w6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3sfntFGhsw%253D%253D&md5=0d3f60acb038faddba05e3d6e183004fChallenges of antibiotic resistance biofilms and potential combating strategies: a reviewKhan Javairia; Tarar Sumbal Mudassar; Arshad Muhammad; Gul Iram; Nawaz Uzam3 Biotech (2021), 11 (4), 169 ISSN:2190-572X.In this modern era, medicine is facing many alarming challenges. Among different challenges, antibiotics are gaining importance. Recent years have seen unprecedented increase in knowledge and understanding of various factors that are root cause of the spread and development of resistance in microbes against antibiotics. The infection results in the formation of microbial colonies which are termed as biofilms. However, it has been found that a multiple factors contribute in the formation of antimicrobial resistance. Due to higher dose of Minimum Bactericidal Concentration (MBC) as well as of Minimum Inhibitory Concentration (MIC), a large batch of antibiotics available today are of no use as they are ineffective against infections. Therefore, to control infections, there is dire need to adopt alternative treatment for biofilm infection other than antibiotics. This review highlights the latest techniques that are being used to cure the menace of biofilm infections. A wide range of mechanisms has been examined with particular attention towards avenues which can be proved fruitful in the treatment of biofilms. Besides, newer strategies, i.e., matrix centered are also discussed as alternative therapeutic techniques including modulating microbial metabolism, matrix degrading enzyme, photodynamic therapy, natural compounds quorum sensing and nanotechnology which are being used to disrupt extra polymeric substances (EPS) matrix of desired bacterial biofilms.
- 7Le, H.; Arnoult, C.; De, E.; Schapman, D.; Galas, L.; Le Cerf, D.; Karakasyan, C. Antibody-Conjugated Nanocarriers for Targeted Antibiotic Delivery: Application in the Treatment of Bacterial Biofilms. Biomacromolecules 2021, 22 (4), 1639– 1653, DOI: 10.1021/acs.biomac.1c000827https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXmtFOhurw%253D&md5=63005cbd75276c74cb9ae06c6c9597c1Antibody-Conjugated Nanocarriers for Targeted Antibiotic Delivery: Application in the Treatment of Bacterial BiofilmsLe, Hung; Arnoult, Christophe; De, Emmanuelle; Schapman, Damien; Galas, Ludovic; Le Cerf, Didier; Karakasyan, CaroleBiomacromolecules (2021), 22 (4), 1639-1653CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)Conventional antibiotic treatment is in most cases insufficient to eradicate biofilm-related infections, resulting in high risk of treatment failure and recurrent infections. Recent studies have shown that novel methods of antibiotic delivery can improve clin. outcomes and reduce the emergence of antibiotic resistance. The objectives of this work were to develop and evaluate a targeting nanocarrier system that enables effective delivery of antimicrobial drugs to Staphylococcus aureus, a commonly virulent human pathogen. For this purpose, we first prepd. a formulation of polymeric nanoparticles (NPs) suitable for encapsulation and sustained release of antibiotics. A specific antibody against S. aureus was used as a targeting ligand and was covalently immobilized onto the surface of nanoparticulate materials. It was demonstrated that the targeting NPs preferentially bound S. aureus cells and presented an elevated accumulation in the S. aureus biofilm. Compared to free-form antibiotic, the antibiotic-loaded targeting NPs significantly enhanced in vitro bactericidal activity against S. aureus both in planktonic and biofilm forms. Using a mouse infection model, we obsd. improved therapeutic efficacy of these antibiotic-loaded NPs after a single i.v. administration. Taken together, our studies show that the targeting nanoparticulate system could be a promising strategy to enhance the biodistribution of antibiotics and thereby improve their efficacy.
- 8Sun, Y.; Liu, Y.; Zhang, B.; Shi, S.; Zhang, T.; Zhao, D.; Tian, T.; Li, Q.; Lin, Y. Erythromycin loaded by tetrahedral framework nucleic acids are more antimicrobial sensitive against Escherichia coli (E. coli). Bioact Mater. 2021, 6 (8), 2281– 2290, DOI: 10.1016/j.bioactmat.2020.12.0278https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtFKjtrrE&md5=87bde11fa4efdc972fa55a07a02864bbErythromycin loaded by tetrahedral framework nucleic acids are more antimicrobial sensitive against Escherichia coli (E. coli)Sun, Yue; Liu, Yuhao; Zhang, Bowen; Shi, Shirong; Zhang, Tao; Zhao, Dan; Tian, Taoran; Li, Qirong; Lin, YunfengBioactive Materials (2021), 6 (8), 2281-2290CODEN: BMIAD4; ISSN:2452-199X. (Elsevier B.V.)Erythromycin is a commonly used broad-spectrum antibiotic, but resistance to this antibiotic makes its use less effective. Considerable efforts, beside finding alternatives, are needed to enhance its antimicrobial effect and stability against bacteria. Tetrahedral framework nucleic acids (tFNAs), a novel delivery vehicle with a three-dimensional nanostructure, have been studied as a carrying platform of antineoplastic drugs. In this study, the use of tFNAs in delivering erythromycin into Escherichia coli (E. coli) was investigated for the first time. The tFNAs vehicle increased the bacterial uptake of erythromycin and promoted membrane destabilization. Moreover, it increased the permeability of the bacterial cell wall, and reduced drug resistance by improving the movement of the drug across the membrane. The tFNAs-based delivery system enhanced the effects of erythromycin against E. coli. It may therefore provide an effective delivery vehicle for erythromycin in targeting antibiotic-resistant bacteria with thick cell wall.
- 9Obuobi, S.; Mayandi, V.; Nor, N. A. M.; Lee, B. J.; Lakshminarayanan, R.; Ee, P. L. R. Nucleic acid peptide nanogels for the treatment of bacterial keratitis. Nanoscale 2020, 12 (33), 17411– 17425, DOI: 10.1039/D0NR03095C9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsF2ntbzP&md5=45781ef2b9111b69331af69e94b59a5fNucleic acid peptide nanogels for the treatment of bacterial keratitisObuobi, Sybil; Mayandi, Venkatesh; Nor, Nurul Azlyn Mohd; Lee, Benedict Jiasheng; Lakshminarayanan, Rajamani; Ee, Pui Lai RachelNanoscale (2020), 12 (33), 17411-17425CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Cage-shaped nucleic acid nanocarriers are promising mol. scaffolds for the organization of polypeptides. However, there is an unmet need for facile loading strategies that truly emulate nature's host-guest systems to drive encapsulation of antimicrobial peptides without loss of biol. activity. Herein, we develop DNA nanogels with rapid in situ loading of L12 peptide during the thermal annealing process. By leveraging the binding affinity of L12 to the polyanionic core, we successfully confine the AMPs within the DNA nanogel. We report that the thermostability of L12 in parallel with the high encapsulation efficiency, low toxicity and sustained drug release of the pre-loaded L12 nanogels can be translated into significant antimicrobial activity. Using an S. aureus model of infectious bacterial keratitis, we observe fast resoln. of clin. symptoms and significant redn. of bacterial bioburden. Collectively, this study paves the way for the development of DNA nanocarriers for caging AMPs with immense significance to address the rise of resistance.
- 10Chi, Q. J.; Yang, Z. C.; Xu, K.; Wang, C. L.; Liang, H. P. DNA Nanostructure as an Efficient Drug Delivery Platform for Immunotherapy. Front. Pharmacol. 2020, 10, 1– 17, DOI: 10.3389/fphar.2019.01585There is no corresponding record for this reference.
- 11Nicolson, F.; Ali, A.; Kircher, M. F.; Pal, S. DNA Nanostructures and DNA-Functionalized Nanoparticles for Cancer Theranostics. Adv. Sci. (Weinh) 2020, 7 (23), 2001669, DOI: 10.1002/advs.20200166911https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3szmtF2lsQ%253D%253D&md5=4ad5e33a240fc39bd664fafc62c22a2cDNA Nanostructures and DNA-Functionalized Nanoparticles for Cancer TheranosticsNicolson Fay; Kircher Moritz F; Nicolson Fay; Kircher Moritz F; Ali Akbar; Pal Suchetan; Kircher Moritz FAdvanced science (Weinheim, Baden-Wurttemberg, Germany) (2020), 7 (23), 2001669 ISSN:2198-3844.In the last two decades, DNA has attracted significant attention toward the development of materials at the nanoscale for emerging applications due to the unparalleled versatility and programmability of DNA building blocks. DNA-based artificial nanomaterials can be broadly classified into two categories: DNA nanostructures (DNA-NSs) and DNA-functionalized nanoparticles (DNA-NPs). More importantly, their use in nanotheranostics, a field that combines diagnostics with therapy via drug or gene delivery in an all-in-one platform, has been applied extensively in recent years to provide personalized cancer treatments. Conveniently, the ease of attachment of both imaging and therapeutic moieties to DNA-NSs or DNA-NPs enables high biostability, biocompatibility, and drug loading capabilities, and as a consequence, has markedly catalyzed the rapid growth of this field. This review aims to provide an overview of the recent progress of DNA-NSs and DNA-NPs as theranostic agents, the use of DNA-NSs and DNA-NPs as gene and drug delivery platforms, and a perspective on their clinical translation in the realm of oncology.
- 12Hui, L.; Xu, A.; Liu, H. DNA-Based Nanofabrication for Antifouling Applications. Langmuir 2019, 35 (38), 12543– 12549, DOI: 10.1021/acs.langmuir.9b0156912https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1ajtbrL&md5=6849132a1f3e80cf7cce572282fd2ce6DNA-Based Nanofabrication for Antifouling ApplicationsHui, Liwei; Xu, Anqin; Liu, HaitaoLangmuir (2019), 35 (38), 12543-12549CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)This paper reports antifouling properties of nanostructured SiO2 substrates patterned by DNA lithog. We used DNA triangle nanostructures as templates to produce triangular-shaped trenches ca. 130 nm in size on SiO2 surfaces. Using B. subtilis as a bacterial model, we found that such nanopatterned surface showed a 75% redn. in bacterial adhesion and 72% redn. in biofilm d. at 35% surface coverage of the nanoscale triangular trenches. DNA-based nanofabrication can produce high-resoln. designer patterns, but aligning these patterns has been one of the major tech. challenges for its applications in nanoelectronics. This work demonstrates the potential of DNA-based nanofabrication in antifouling applications, where surface patterning of micro/nanostructures is required but not their precise alignment.
- 13Mela, I.; Vallejo-Ramirez, P. P.; Makarchuk, S.; Christie, G.; Bailey, D.; Henderson, R. M.; Sugiyama, H.; Endo, M.; Kaminski, C. F. DNA Nanostructures for Targeted Antimicrobial Delivery. Angew. Chem., Int. Ed. 2020, 59 (31), 12698– 12702, DOI: 10.1002/anie.20200274013https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXpsl2ksbo%253D&md5=287d9b69f966370aa62e0e2eb247affcDNA Nanostructures for Targeted Antimicrobial DeliveryMela, Ioanna; Vallejo-Ramirez, Pedro P.; Makarchuk, Stanislaw; Christie, Graham; Bailey, David; Henderson, Robert M.; Sugiyama, Hiroshi; Endo, Masayuki; Kaminski, Clemens F.Angewandte Chemie, International Edition (2020), 59 (31), 12698-12702CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)We report the use of DNA origami nanostructures, functionalized with aptamers, as a vehicle for delivering the antibacterial enzyme lysozyme in a specific and efficient manner. We test the system against Gram-pos. (Bacillus subtilis) and Gram-neg. (Escherichia coli) targets. We use direct stochastic optical reconstruction microscopy (dSTORM) and at. force microscopy (AFM) to characterize the DNA origami nanostructures and structured illumination microscopy (SIM) to assess the binding of the origami to the bacteria. We show that treatment with lysozyme-functionalized origami slows bacterial growth more effectively than treatment with free lysozyme. Our study introduces DNA origami as a tool in the fight against antibiotic resistance, and our results demonstrate the specificity and efficiency of the nanostructure as a drug delivery vehicle.
- 14Hu, S. Q.; Yi, T. T.; Huang, Z. C.; Liu, B. W.; Wang, J. X.; Yi, X. Y.; Liu, J. W. Etching silver nanoparticles using DNA. Mater. Horiz. 2019, 6 (1), 155– 159, DOI: 10.1039/C8MH01126E14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVOjtLbJ&md5=d24295d5c6f42e2a3a5501e5415f02bcEtching silver nanoparticles using DNAHu, Shengqiang; Yi, Tiantian; Huang, Zhicheng; Liu, Biwu; Wang, Jianxiu; Yi, Xinyao; Liu, JuewenMaterials Horizons (2019), 6 (1), 155-159CODEN: MHAOBM; ISSN:2051-6355. (Royal Society of Chemistry)While DNA has been widely used for directing the growth and assembly of nanomaterials, the reverse reaction, etching nanoparticles using DNA, has yet to be demonstrated. We herein communicate that poly-cytosine (poly-C) DNA can efficiently etch silver nanoparticles (AgNPs) followed by Ostwald ripening at higher DNA concns. The etching process was precisely controlled by varying the length, sequence, and concn. of DNA, and the no. of consecutive cytosines is particularly important for the efficacy of etching. In addn. to spherical AgNPs, etching also occurred for silver nanoplates displaying interesting color changes. Compared to other chem. etching agents such as H2O2 and ferricyanide, DNA is highly biocompatible, allowing biol. applications. Poly-C etching enhanced the cytotoxicity of AgNPs against cancer cells, and Gram-pos. and Gram-neg. bacterial cells. This study will stimulate many related studies in DNA nanotechnol., bioanal. sensors and nanomedicine.
- 15Obuobi, S.; Julin, K.; Fredheim, E. G. A.; Johannessen, M.; Skalko-Basnet, N. Liposomal delivery of antibiotic loaded nucleic acid nanogels with enhanced drug loading and synergistic anti-inflammatory activity against S. aureus intracellular infections. J. Controlled Release 2020, 324, 620– 632, DOI: 10.1016/j.jconrel.2020.06.00215https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtFOhsbvJ&md5=84749b577c27b50e6b7ac743d6f68c9eLiposomal delivery of antibiotic loaded nucleic acid nanogels with enhanced drug loading and synergistic anti-inflammatory activity against S. aureus intracellular infectionsObuobi, Sybil; Julin, Kjersti; Fredheim, Elizabeth G. A.; Johannessen, Mona; Skalko-Basnet, NatasaJournal of Controlled Release (2020), 324 (), 620-632CODEN: JCREEC; ISSN:0168-3659. (Elsevier B.V.)The persistence of Staphylococcus aureus has been accredited to its ability to escape immune response via host cell invasion. Despite the efficacy of many antibiotics against S. aureus, the high extracellular concns. of conventional antibiotics required for bactericidal activity is limited by their low cellular accumulation and poor intracellular retention. While nanocarriers have received tremendous attention for antibiotic delivery against persistent pathogens, they suffer daunting challenges such as low drug loading, poor retention and untimely release of hydrophilic cargos. Here, a hybrid system (Van_DNL) is fabricated wherein nucleic acid nanogels are caged within a liposomal vesicle for antibiotic delivery. The central principle of this approach relies on exploiting non-covalent electrostatic interactions between cationic cargos and polyanionic DNA to immobilize antibiotics and enable precise temporal release against intracellular S. aureus. In vitro characterization of Van_DNL revealed a stable homogenous formulation with circular morphol. and enhanced vancomycin loading efficiency. The hybrid system significantly sustained the release of vancomycin over 24 h compared to liposomal or nanogel controls. Under enzymic conditions relevant to S. aureus infections, lipase triggered release of vancomycin was obsd. from the hybrid. While using Van_DNL to treat S. aureus infected macrophages, a dose dependent redn. in intracellular bacterial load was obsd. over 24 h and exposure to Van_DNL for 48 h caused negligible cellular toxicity. Pre-treatment of macrophages with the antimicrobial hybrid resulted in a strong anti-inflammatory activity in synergy with vancomycin following endotoxin stimulation. Conceptually, these findings highlight these hybrids as a unique and universal platform for synergistic antimicrobial and anti-inflammatory therapy against persistent infections.
- 16Pang, Y. Y.; Schwartz, J.; Thoendel, M.; Ackermann, L. W.; Horswill, A. R.; Nauseef, W. M. agr-Dependent interactions of Staphylococcus aureus USA300 with human polymorphonuclear neutrophils. J. Innate Immun. 2010, 2 (6), 546– 59, DOI: 10.1159/00031985516https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht12lurzE&md5=298816719f91b27d01ad917c45131fa8agr-Dependent Interactions of Staphylococcus aureus USA300 with Human Polymorphonuclear NeutrophilsPang, Yun Yun; Schwartz, Jamie; Thoendel, Matthew; Ackermann, Laynez W.; Horswill, Alexander R.; Nauseef, William M.Journal of Innate Immunity (2010), 2 (6), 546-559CODEN: JIIOB2; ISSN:1662-811X. (S. Karger AG)The emergence of serious infections due to community-assocd. methicillin-resistant Staphylococcus aureus (CA-MRSA) has fueled interest in the contributions of specific staphylococcal virulence factors to clin. disease. To assess the contributions of agr-dependent factors to the fate of organisms in polymorphonuclear neutrophils (PMN), we examd. the consequences for organism and host cells of feeding PMN with wild-type CA-MRSA (LAC) or CA-MRSA (LAC agr KO) at different multiplicities of infection (MOIs). Phagocytosed organisms rapidly increased the transcription of RNAIII in a time- and MOI-dependent fashion; extracellular USA300 (LAC) did not increase RNAIII expression despite having the capacity to respond to autoinducing peptide-enriched culture medium. HOCl-mediated damage and intracellular survival were the same in the wild-type and USA300 (LAC agr KO). PMN lysis by ingested USA300 (LAC) was time- and MOI-dependent and, at MOIs >1, required α-hemolysin (hla) as USA300 (LAC agr KO) and USA300 (LAC hla KO) promoted PMN lysis only at high MOIs. Taken together, these data demonstrate activation of the agr operon in human PMN with the subsequent prodn. of α-hemolysin and PMN lysis. The extent to which these events in the phagosomes of human PMN contribute to the increased morbidity and mortality of infections with USA300 (LAC) merits further study.
- 17Obuobi, S.; Tay, H. K.; Tram, N. D. T.; Selvarajan, V.; Khara, J. S.; Wang, Y.; Ee, P. L. R. Facile and efficient encapsulation of antimicrobial peptides via crosslinked DNA nanostructures and their application in wound therapy. J. Controlled Release 2019, 313, 120– 130, DOI: 10.1016/j.jconrel.2019.10.01317https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitVelurrI&md5=285a216b62ad656e022d199751ce2e42Facile and efficient encapsulation of antimicrobial peptides via crosslinked DNA nanostructures and their application in wound therapyObuobi, Sybil; Tay, Hilda Kai-Lin; Tram, Nhan Dai Thien; Selvarajan, Vanitha; Khara, Jasmeet Singh; Wang, Ying; Ee, Pui Lai RachelJournal of Controlled Release (2019), 313 (), 120-130CODEN: JCREEC; ISSN:0168-3659. (Elsevier B.V.)There is growing interest in the development of nucleic acid nanostructures as smart functional materials for applications in drug delivery. Inspired by the diverse phys. interactions that exist in nature, crosslinked DNA nanostructures can serve as attractive affinity binding networks that interact with therapeutic cargos or living cells. Herein we report a strategy that addresses the challenges of topical oligopeptide therapy by exploiting high binding affinity between polyanionic DNA nanostructures and cationic antimicrobial peptides (AMPs) to fabricate hydrogels that release a model antimicrobial L12 peptide in response to pathogenic S. aureus infections. We further demonstrated controlled peptide release profiles via the DNA hydrogels that were biocompatible and delivered superior antimicrobial activity against nuclease-releasing susceptible and methicillin-resistant S. aureus infections. Single application of the L12-loaded DNA hydrogels on porcine explant S. aureus infections revealed potent efficacy after 24 h. As a result of the capacity of the crosslinked DNA nanostructures to elicit a strong anti-inflammatory response, in vivo treatment of mice excision wounds translated into faster healing rates. Overall, the crosslinked DNA nanostructures reported in this study offer significant advantage as functional wound dressings and their future adaptation holds equally great promise for the delivery of cationic antimicrobials.
- 18Singh, N.; Romero, M.; Travanut, A.; Monteiro, P. F.; Jordana-Lluch, E.; Hardie, K. R.; Williams, P.; Alexander, M. R.; Alexander, C. Dual bioresponsive antibiotic and quorum sensing inhibitor combination nanoparticles for treatment of Pseudomonas aeruginosa biofilms in vitro and ex vivo. Biomater. Sci. 2019, 7 (10), 4099– 4111, DOI: 10.1039/C9BM00773C18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsVGgsrjN&md5=8120b77dfb09868ceb0c926ad411a23dDual bioresponsive antibiotic and quorum sensing inhibitor combination nanoparticles for treatment of Pseudomonas aeruginosa biofilms in vitro and ex vivoSingh, Nishant; Romero, Manuel; Travanut, Alessandra; Monteiro, Patricia F.; Jordana-Lluch, Elena; Hardie, Kim R.; Williams, Paul; Alexander, Morgan R.; Alexander, CameronBiomaterials Science (2019), 7 (10), 4099-4111CODEN: BSICCH; ISSN:2047-4849. (Royal Society of Chemistry)Many debilitating infections result from persistent microbial biofilms that do not respond to conventional antibiotic regimens. A potential method to treat such chronic infections is to combine agents which interfere with bacterial biofilm development together with an antibiotic in a single formulation. Here, we explore the use of a new bioresponsive polymer formulation derived from specifically modified alginate nanoparticles (NPs) in order to deliver ciprofloxacin (CIP) in combination with the quorum sensing inhibitor (QSI) 3-amino-7-chloro-2-nonylquinazolin-4(3H)-one (ACNQ) to mature Pseudomonas aeruginosa biofilms. The alginate NPs were engineered to incorporate a pH-responsive linker between the polysaccharide backbone and the QSI, and to encapsulate CIP via charge-charge interactions of the pos.-charged drug with the carboxyl residues of the alginate matrix. In this way, a dual-action release of antibiotic and QSI was designed for the low-pH regions of a biofilm, involving cleavage of the QSI-linker to the alginate matrix and reduced charge-charge interactions between CIP and the polysaccharide as the alginate carboxyl side-chains protonated. When tested in a biofilm model the concomitant release of CIP + QSI from the pH-responsive nanoparticles significantly reduced the viability of the biofilm compared with CIP treatment alone. In addn., the alginate NPs were shown to penetrate deeply into P. aeruginosa biofilms, which we attribute in part to the charges of the NPs and the release of the QSI agent. Finally, we tested the formulation in both a 2D keratinocyte and a 3D ex vivo skin infection model. The dual-action bio-responsive QSI and CIP release nanoparticles effectively cleared the infection in the latter, suggesting considerable promise for combination therapeutics which prevent biofilm formation as well as effectively killing mature P. aeruginosa biofilms.
- 19Hafez, I. M.; Cullis, P. R. Cholesteryl hemisuccinate exhibits pH sensitive polymorphic phase behavior. Biochim. Biophys. Acta, Biomembr. 2000, 1463 (1), 107– 14, DOI: 10.1016/S0005-2736(99)00186-819https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXjtV2ntQ%253D%253D&md5=bb607053ffb66c261b29b02d111dc5f4Cholesteryl hemisuccinate exhibits pH sensitive polymorphic phase behaviorHafez, I. M.; Cullis, P. R.Biochimica et Biophysica Acta, Biomembranes (2000), 1463 (1), 107-114CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)Cholesteryl hemisuccinate (CHEMS) is an acidic cholesterol ester that self-assembles into bilayers in alk. and neutral aq. media and is commonly employed in mixts. with dioleoylphosphatidylethanolamine (DOPE) to form 'pH sensitive' fusogenic vesicles. We show here that CHEMS itself exhibits pH sensitive polymorphism. This is evident from the fusogenic properties of large unilamellar vesicles (LUV) composed of CHEMS and direct visualization employing freeze-fracture electron microscopy. Below pH 4.3, LUV composed of CHEMS undergo fusion as monitored by lipid mixing assays and freeze-fracture electron micrographs reveal the characteristic striated signature of H‖ phase lipid. It is suggested that the pH dependent phase preferences of CHEMS contribute to the pH sensitivity of LUV composed of mixts. of CHEMS and DOPE.
- 20Sun, X.; Zhang, Z. Optimizing the novel formulation of liposome-polycation-DNA complexes (LPD) by central composite design. Arch. Pharmacal Res. 2004, 27 (7), 797– 805, DOI: 10.1007/BF0298015120https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmsFeru78%253D&md5=b5a48a01a6cb5754424485b08d06a5dfOptimizing the novel formulation of liposome-polycation-DNA complexes (LPD) by central composite designSun, Xun; Zhang, ZhirongArchives of Pharmacal Research (2004), 27 (7), 797-805CODEN: APHRDQ; ISSN:0253-6269. (Pharmaceutical Society of Korea)LPD vectors are non-viral vehicles for gene delivery comprised of polycation-condensed plasmid DNA and liposomes. Here, we described a novel anionic LPD formulation contg. protamine-DNA complexes and pH sensitive liposomes composed of DOPE and cholesteryl hemisuccinate (Chems). Central composite design (CCD) was employed to optimize stable LPD formulation with small particle size. A three factor, five-level CCD design was used for the optimization procedure, with the wt. ratio of protamine/DNA (X1), the wt. ratio of Chems/DNA (X2) and the molar ratio of Chems/DOPE in the anionic liposomes (X3) as the independent variables. LPD size (Y1) and LPD protection efficiency against nuclease (Y2) were response variables. Zeta potential detn. was utilized to define the exptl. design region. Based on exptl. design, responses for the 15 formulations were obtained. Math. equations and response surface plots were used to relate the dependent and independent variables. The math. model predicted optimized X1-X3 levels that achieve the desired particle size and the protection efficiency against nuclease. According to these levels, an optimized LPD formulation was prepd., resulting in a particle size of 185.3 nm and protection efficiency of 80.22%.
- 21Fillion, P.; Desjardins, A.; Sayasith, K.; Lagace, J. Encapsulation of DNA in negatively charged liposomes and inhibition of bacterial gene expression with fluid liposome-encapsulated antisense oligonucleotides. Biochim. Biophys. Acta, Biomembr. 2001, 1515 (1), 44– 54, DOI: 10.1016/S0005-2736(01)00392-321https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXnsVSmtLw%253D&md5=6021dae68388bf2b42c60a8cf1064005Encapsulation of DNA in negatively charged liposomes and inhibition of bacterial gene expression with fluid liposome-encapsulated antisense oligonucleotidesFillion, P.; Desjardins, A.; Sayasith, K.; Lagace, J.Biochimica et Biophysica Acta, Biomembranes (2001), 1515 (1), 44-54CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)Antisense therapy for the treatment of bacterial infections is a very attractive alternative to overcome drug resistance problems. However, the penetration of antisense oligonucleotides into bacterial cells is a major huddle that has delayed research and application in this field. In the first part of this study, we defined efficient conditions to encapsulate plasmid DNA and antisense oligonucleotides in a fluid neg. charged liposome. Subsequently, we evaluated the potential of liposome-encapsulated antisense oligonucleotides to penetrate the bacterial outer membrane and to inhibit gene expression in bacteria. It was found that 48.9±12% and 43.5±4% of the purified plasmid DNA and antisense oligonucleotides were resp. encapsulated in the liposomes. Using fluorescence-activated cell sorting anal., it was shown, after subtraction of the fluorescence values due to the aggregation phenomenon measured at 4°, that about 57% of bacterial cells had integrated the encapsulated antisense oligonucleotides whereas values for free antisenses were negligible. The uptake of the encapsulated anti-lacZ antisense oligonucleotides resulted in a 42% redn. of β-galactosidase compared to 9% and 6% for the encapsulated mismatch antisense oligonucleotides and the free antisense oligonucleotides, resp. This work shows that it is possible to encapsulate relatively large quantities of neg. charged mols. in neg. fluid liposomes and suggests that fluid liposomes could be used to deliver nucleic acids in bacteria to inhibit essential bacterial genes.
- 22Mozafari, M. R.; Hasirci, V. Mechanism of calcium ion induced multilamellar vesicle-DNA interaction. J. Microencapsulation 1998, 15 (1), 55– 65, DOI: 10.3109/0265204980900683522https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXhs1KltLk%253D&md5=392406d6ec0bbf0acf7f6741521873c1Mechanism of calcium ion induced multilamellar vesicle-DNA interactionMozafari, M. R.; Hasirci, V.Journal of Microencapsulation (1998), 15 (1), 55-65CODEN: JOMIEF; ISSN:0265-2048. (Taylor & Francis Ltd.)The effect of Ca2+ on the DNA interaction with anionic and neutral multi-lamellar vesicles (MLV) has been investigated. DNA from wheat (Triticum aestivum) was introduced to a suspension of MLV, composed of phosphatidylcholine (PC):dicetylphosphate (DCP):cholesterol (CHOL) at different molar ratios, to which Ca2+ (5-75 mM) was subsequently added. Indication of aggregation and/or fusion was obtained via light-scattering examn. following the addn. of Ca2+ and DNA to the MLV medium. Using a UV spectrophotometric assay, it was obsd. that although DNA alone has no effect on neg. charged MLV, it enhances liposomal interaction in the presence of calcium ions. The minimal Ca2+ concn. required to promote the interaction was detected to be 10 mM, and the highest level of interaction was obsd. at 75 mM. The aggregation/fusion of vesicles was detected for uncharged MLV (with no DCP in their structure), as well as for the anionic ones contg. c. 10% CHOL, but not for anionic MLV contg. 40% CHOL. This is explained in terms of cholesterol decreasing the membrane fluidity (above the Tc of components) as a result of which more rigid vesicles become less prone to aggregation/fusion interactions.
- 23Grit, M.; Crommelin, J. A. Chemical-Stability of Liposomes - Implications for Their Physical Stability. Chem. Phys. Lipids 1993, 64 (1–3), 3– 18, DOI: 10.1016/0009-3084(93)90053-623https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXmslyntrs%253D&md5=41e621a6f027d4b2a135ec55a8f2edd8Chemical stability of liposomes: Implications for their physical stabilityGrit, Mustafa; Crommelin, Daan J. A.Chemistry and Physics of Lipids (1993), 64 (1-3), 3-18CODEN: CPLIA4; ISSN:0009-3084.A review with 56 refs.; in the first part of this article, chem. and phys. stability of aq. liposome dispersions have been addressed. Chem. stability of phospholipids has been considered in two parts: oxidn. and hydrolysis. Major attention has been paid to hydrolysis kinetics of phospholipids as a function of pH, temp., buffer concn. and ionic strength. Furthermore, the effect of chain length, head group, state of aggregation, addn. of cholesterol and presence of charge on the hydrolysis kinetics of phospholipids has been dealt with. In the second part phys. stability of chem. degraded liposome dispersions has been evaluated. In the final part quality control assays for liposome dispersions is presented and a HPLC method with a refractive index detector for the anal. of phospholipids from aq. liposome dispersions is described.
- 24Bhattacharjee, S. DLS and zeta potential - What they are and what they are not?. J. Controlled Release 2016, 235, 337– 351, DOI: 10.1016/j.jconrel.2016.06.01724https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFOgt73O&md5=50555ae8bc84aff2dc92b1c2d24dcf80DLS and zeta potential - What they are and what they are not?Bhattacharjee, SouravJournal of Controlled Release (2016), 235 (), 337-351CODEN: JCREEC; ISSN:0168-3659. (Elsevier B.V.)A review. Adequate characterization of NPs (nanoparticles) is of paramount importance to develop well defined nanoformulations of therapeutic relevance. Detn. of particle size and surface charge of NPs are indispensable for proper characterization of NPs. DLS (dynamic light scattering) and ZP (zeta potential) measurements have gained popularity as simple, easy and reproducible tools to ascertain particle size and surface charge. Unfortunately, on practical grounds plenty of challenges exist regarding these two techniques including inadequate understanding of the operating principles and dealing with crit. issues like sample prepn. and interpretation of the data. As both DLS and ZP have emerged from the realms of phys. colloid chem. - it is difficult for researchers engaged in nanomedicine research to master these two techniques. Addnl., there is little literature available in drug delivery research which offers a simple, concise account on these techniques. This review tries to address this issue while providing the fundamental principles of these techniques, summarizing the core math. principles and offering practical guidelines on tackling commonly encountered problems while running DLS and ZP measurements. Finally, the review tries to analyze the relevance of these two techniques from translatory perspective.
- 25Smistad, G.; Jacobsen, J.; Sande, S. A. Multivariate toxicity screening of liposomal formulations on a human buccal cell line. Int. J. Pharm. 2007, 330 (1–2), 14– 22, DOI: 10.1016/j.ijpharm.2006.08.04425https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntFSgtQ%253D%253D&md5=543a91785cf7f58a0931c44831fe4751Multivariate toxicity screening of liposomal formulations on a human buccal cell lineSmistad, Gro; Jacobsen, Jette; Sande, Sverre A.International Journal of Pharmaceutics (2007), 330 (1-2), 14-22CODEN: IJPHDE; ISSN:0378-5173. (Elsevier Ltd.)The influence of various formulation factors on the in vitro cellular toxicity of liposomes on human buccal cells (TR146), were studied by using the concept of statistical exptl. design and multivariate evaluation. The factors investigated were the type of main phospholipid (egg-PC, DMPC, DPPC), lipid concn., the type of charge, liposome size, and amt. and nature of the charged component (diacyl-PA, diacyl-PG, diacyl-PS, stearylamine (SA), diacyl-TAP) in the liposomes. Both full factorial design and D-optimal designs were created. Several significant main factors and interactions were revealed. Pos. charged liposomes were shown to be toxic. The toxicity of neg. charged liposomes was relatively low. Diacyl-TAP was less toxic than SA, and DPPC was less toxic than DMPC. Low level of pos. charged component was favorable and essential when using egg-PC as the main lipid. The amt. of neg. charged component, the liposome size, and the total lipid concn. did not affect the toxicity within the exptl. room. DPPC appeared to be a good candidate when formulating both pos. and neg. charged liposomes with low cellular toxicity. The concept of statistical exptl. design and multivariate evaluation was shown to be a useful approach in cell toxicity screening studies.
- 26Dokka, S.; Toledo, D.; Shi, X. G.; Castranova, V.; Rojanasakul, Y. Oxygen radical-mediated pulmonary toxicity induced by some cationic liposomes. Pharm. Res. 2000, 17 (5), 521– 525, DOI: 10.1023/A:100750461335126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXksVGqtbc%253D&md5=136d087f5e3b709d42ddb2dbd430a7cfOxygen radical-mediated pulmonary toxicity induced by some cationic liposomesDokka, Sujatha; Toledo, David; Shi, Xianglin; Castranova, Vincent; Rojanasakul, YonPharmaceutical Research (2000), 17 (5), 521-525CODEN: PHREEB; ISSN:0724-8741. (Kluwer Academic/Plenum Publishers)The objectives of this study are to investigate the toxicity assocd. with polycationic liposomes and to elucidate the underlying mechanism. We tested the hypothesis that the pos. charge of liposomes is a key determinant of toxicity by testing differently charged liposomes in mice. Differently charged liposomal systems including cationic liposomes, LipofectAMINE and DOTAP, and neutral and neg. liposomes were evaluated for their toxicity after pulmonary administration in mice. LDH assay and differential cell counts were performed to measure toxicity and pulmonary inflammation, resp. Reactive oxygen intermediates (ROI) were assessed by chemiluminescence. Instillation of cationic liposomes elicited dose-dependent toxicity and pulmonary inflammation. This effect was more pronounced with the multivalent cationic liposome LipofectAMINE as compared to the monovalent cationic DOTAP. Neutral and neg. liposomes did not exhibit lung toxicity. Toxicity assocd. with cationic liposomes correlated with the oxidative burst induced by the liposomes. LipofectAMINE induced a dose-dependent increase in ROI generation. This effect was less pronounced with DOTAP and absent with neutral and neg. liposomes. ROI play a key role in cationic lipid-mediated toxicity. Polyvalent cationic liposomes cause a release of ROI which are responsible for the pulmonary toxicity.
- 27Sudimack, J. J.; Guo, W.; Tjarks, W.; Lee, R. J. A novel pH-sensitive liposome formulation containing oleyl alcohol. Biochim. Biophys. Acta, Biomembr. 2002, 1564 (1), 31– 7, DOI: 10.1016/S0005-2736(02)00399-127https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XkvFGkt7s%253D&md5=d9666d3a28962812843290d7827b8b4eA novel pH-sensitive liposome formulation containing oleyl alcoholSudimack, Jennifer J.; Guo, Wenjin; Tjarks, Werner; Lee, Robert J.Biochimica et Biophysica Acta, Biomembranes (2002), 1564 (1), 31-37CODEN: BBBMBS; ISSN:0005-2736. (Elsevier B.V.)PH-sensitive liposomes are designed to undergo acid-triggered destabilization. First generation pH-sensitive liposomes, based on the cone-shaped lipid dioleoylphosphatidylethanolamine (DOPE), have been shown to lose fusogenicity in the presence of serum. Here, we report the design and evaluation of novel serum-resistant pH-sensitive liposome formulations that are based on the compn. of egg phosphatidylcholine (PC), cholesteryl hemisuccinate (CHEMS), oleyl alc. (OAlc), and Tween-80 (T-80). When loaded with the fluorescent probe calcein, these liposomes exhibited excellent stability at pH 7.4 and underwent rapid destabilization upon acidification as shown by calcein dequenching and particle size increase. Adjusting the mole percentages of T-80 and OAlc in the formulation could regulate the stability and pH-sensitive properties of these liposomes. Liposomes with a higher T-80 content exhibited greater stability but were less sensitive to acid-induced destabilization. Meanwhile, formulations with a higher OAlc content exhibited greater content release in response to low pH. The pH-triggered liposomal destabilization did not produce membrane fusion according to an octadecylrhodamine B chloride (R18) lipid-mixing assay. Compared to DOPE-based pH-sensitive liposomes, the above formulations showed much better retention of their pH-sensitive properties in the presence of 10% serum. These liposomes were then evaluated for intracellular delivery of entrapped cytosine-β-d-arabinofuranoside (araC) in KB human oral cancer cells, which have elevated folate receptor (FR) expression. The FR, which is amplified in many types of human tumors, has been shown to mediate the internalization of folate-derivatized liposomes into an acidic intracellular compartment. FR-targeted OAlc-based pH-sensitive liposomes, entrapping 200 mM araC, showed ∼17-times greater FR-dependent cytotoxicity in KB cells compared to araC delivered via FR-targeted non-pH-sensitive liposomes. These data indicated that pH-sensitive liposomes based on OAlc, combined with FR-mediated targeting, are promising delivery vehicles for membrane impermeable therapeutic agents.
- 28Mann, E. E.; Wozniak, D. J. Pseudomonas biofilm matrix composition and niche biology. FEMS Microbiol Rev. 2012, 36 (4), 893– 916, DOI: 10.1111/j.1574-6976.2011.00322.x28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xht1OgsL3E&md5=cbdb3348bfd43f0e6995858f5c621793Pseudomonas biofilm matrix composition and niche biologyMann, Ethan E.; Wozniak, Daniel J.FEMS Microbiology Reviews (2012), 36 (4), 893-916CODEN: FMREE4; ISSN:0168-6445. (Wiley-Blackwell)Review. Biofilms are a predominant form of growth for bacteria in the environment and in the clinic. Crit. for biofilm development are adherence, proliferation, and dispersion phases. Each of these stages includes reinforcement by, or modulation of, the extracellular matrix. Pseudomonas aeruginosa has been a model organism for the study of biofilm formation. Addnl., other Pseudomonas species utilize biofilm formation during plant colonization and environmental persistence. Pseudomonads produce several biofilm matrix mols., including polysaccharides, nucleic acids, and proteins. Accessory matrix components shown to aid biofilm formation and adaptability under varying conditions are also produced by pseudomonads. Adaptation facilitated by biofilm formation allows for selection of genetic variants with unique and distinguishable colony morphol. Examples include rugose small-colony variants and wrinkly spreaders (WS), which over produce Psl/Pel or cellulose, resp., and mucoid bacteria that over produce alginate. The well-documented emergence of these variants suggests that pseudomonads take advantage of matrix-building subpopulations conferring specific benefits for the entire population. This review focuses on various polysaccharides as well as addnl. Pseudomonas biofilm matrix components. Discussions center on structure-function relationships, regulation, and the role of individual matrix mols. in niche biol.
- 29Sorroche, F.; Bogino, P.; Russo, D. M.; Zorreguieta, A.; Nievas, F.; Morales, G. M.; Hirsch, A. M.; Giordano, W. Cell Autoaggregation, Biofilm Formation, and Plant Attachment in a Sinorhizobium meliloti lpsB Mutant. Mol. Plant-Microbe Interact. 2018, 31 (10), 1075– 1082, DOI: 10.1094/MPMI-01-18-0004-R29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlSmsr3J&md5=5b569b743955926ffa77bc62f75c848bCell autoaggregation, biofilm formation, and plant attachment in a sinorhizobium meliloti lpsb mutantSorroche, Fernando; Bogino, Pablo; Russo, Daniela M.; Zorreguieta, Angeles; Nievas, Florela; Morales, Gustavo M.; Hirsch, Ann M.; Giordano, WalterMolecular Plant-Microbe Interactions (2018), 31 (10), 1075-1082CODEN: MPMIEL; ISSN:0894-0282. (APS Press)Bacterial surface mols. arc crucial for the establishment of a successful rhizobia-legume symbiosis, and, in most bacteria, arc also crit. for adherence properties, surface colonization, and as a barrier for defense. Rhizobial mutants defective in the prodn. of exopolysaccharides (EPSs), lipopolysaccharides (LPSs), or capular polysacchar ides are usually affected in symbiosis with their plant hosts. In the present study, we evaluated the role of the combined effects of LPS and EPS II in cell-to-cell and cell-to-surface interactions in Sinorlli-zohium meliloti by studying planktonic cell autoaggrcgation, biofilm formation, and symbiosis with the host plant Medicago sativa. The lpsB mutant, which has a defective core portion of LPS, exhibited a redn. in biofilm formation on a biotic surfaces as well as altered biofilm architecture compared with the wild-type Rm8530 strain. Atomic force microscopy and confocal laser microscopy revealed an increase in polar cell-to-cell inter actions in the IpsB mutant, which might account for the biofilm deficiency. However. a certain level of biofilm development was obsd. in the lpsB strain compared with the EPS 11-defective mutant strains. Autoaggregation expts. carried out with LPS and EPS mutant strains showed that both polysaccharides have an impact on the cell-to-cell adhesive interactions of planktonic bacteria. Although the IpsB mutation and the loss of EPS prodn. strongly stimulated early :attachment to alfalfa roots, the no. of nodules induced in M. sativa was not increased. Taken together, this work demonstrates that S. meliloti interactions with biotic and abiotic surfaces depend on the interplay between LPS and EPS II.
- 30Coulon, C.; Vinogradov, E.; Filloux, A.; Sadovskaya, I. Chemical analysis of cellular and extracellular carbohydrates of a biofilm-forming strain Pseudomonas aeruginosa PA14. PLoS One 2010, 5 (12), e14220, DOI: 10.1371/journal.pone.001422030https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFGqu7jM&md5=679127e9a16522913c471f6572e66952Chemical analysis of cellular and extracellular carbohydrates of a biofilm-forming strain Pseudomonas aeruginosa PA14Coulon, Charlene; Vinogradov, Evgeny; Filloux, Alain; Sadovskaya, IrinaPLoS One (2010), 5 (12), e14220CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)Pseudomonas aeruginosa is a Gram-neg. bacterium and an opportunistic pathogen that causes persisting life-threatening infections in cystic fibrosis (CF) patients. Biofilm mode of growth facilitates its survival in a variety of environments. Most P. aeruginosa isolates, including the non-mucoid lab. strain PA14, are able to form a thick pellicle, which results in a surface-assocd. biofilm at the air-liq. (A-L) interface in standing liq. cultures. Exopolysaccharides (EPS) are considered as key components in the formation of this biofilm pellicle. In the non-mucoid P. aeruginosa strain PA14, the "scaffolding" polysaccharides of the biofilm matrix, and the mols. responsible for the structural integrity of rigid A-L biofilm have not been identified. Moreover, the role of LPS in this process is unclear, and the chem. structure of the LPS O-antigen of PA14 has not yet been elucidated. Principal Findings: In the present work we carried out a systematic anal. of cellular and extracellular (EC) carbohydrates of P. aeruginosa PA14. The authors also elucidated the chem. structure of the LPS O-antigen by chem. methods and 2-D NMR spectroscopy. It is composed of linear trisaccharide repeating units, identical to those described for P. aeruginosa Lanyi type O:2a,c (Lanyi-Bergman O-serogroup 10a, 10c; IATS serotype 19). Furthermore, an EC O-antigen polysaccharide (EC O-PS) and the glycerol-phosphorylated cyclic β-(1,3)-glucans were identified in the culture supernatant of PA14, grown statically in minimal medium. Finally, the extracellular matrix of the thick biofilm formed at the A-L interface contained, in addn. to eDNA, important quantities (at least ∼20% of dry wt.) of LPS-like material. Thus, the authors characterized the chem. structure of the LPS O-antigen and showed that the O-antigen polysaccharide is an abundant extracellular carbohydrate of PA14. They present evidence that LPS-like material is found as a component of a biofilm matrix of P. aeruginosa.
- 31Schooling, S. R.; Beveridge, T. J. Membrane vesicles: an overlooked component of the matrices of biofilms. J. Bacteriol. 2006, 188 (16), 5945– 57, DOI: 10.1128/JB.00257-0631https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XosVehtbo%253D&md5=70bb1a3d1f3b6a58911f3eeca87dbbcfMembrane vesicles: an overlooked component of the matrices of biofilmsSchooling, Sarah R.; Beveridge, Terry J.Journal of Bacteriology (2006), 188 (16), 5945-5957CODEN: JOBAAY; ISSN:0021-9193. (American Society for Microbiology)The matrix helps define the architecture and infrastructure of biofilms and also contributes to their resilient nature. Although many studies continue to define the properties of both gram-pos. and gram-neg. bacterial biofilms, there is still much to learn, esp. about how structural characteristics help bridge the gap between the chem. and phys. aspects of the matrix. Here, we show that membrane vesicles (MVs), structures derived from the outer membrane of gram-neg. bacteria, are a common particulate feature of the matrix of Pseudomonas aeruginosa biofilms. Biofilms grown using different model systems and growth conditions were shown to contain MVs when thin sectioned for TEM, and mech. disrupted biofilms revealed MVs in assocn. with intercellular material. MVs were also isolated from biofilms by employing techniques for matrix isolation and a modified MV isolation protocol. Together these observations verified the presence and frequency of MVs and indicated that MVs were a definite component of the matrix. Characterization of planktonic and biofilm-derived MVs revealed quant. and qual. differences between the two and indicated functional roles, such as proteolytic activity and binding of antibiotics. The ubiquity of MVs was supported by observations of biofilms from a variety of natural environments outside the lab. and established MVs as common biofilm constituents. MVs appear to be important and relatively unacknowledged particulate components of the matrix of gram-neg. or mixed bacterial biofilms.
- 32Jabbouri, S.; Sadovskaya, I. Characteristics of the biofilm matrix and its role as a possible target for the detection and eradication of Staphylococcus epidermidis associated with medical implant infections. FEMS Immunol. Med. Microbiol. 2010, 59 (3), 280– 91, DOI: 10.1111/j.1574-695X.2010.00695.x32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtVeju77I&md5=c928c7c90bbd5a7ecbe48174b09d8855Characteristics of the biofilm matrix and its role as a possible target for the detection and eradication of Staphylococcus epidermidis associated with medical implant infectionsJabbouri, Said; Sadovskaya, IrinaFEMS Immunology and Medical Microbiology (2010), 59 (3), 280-291CODEN: FIMIEV; ISSN:0928-8244. (Wiley-Blackwell)The virulence of Staphylococcus epidermidis is related to its capacity to form biofilms. Such biofilm-related infections are extremely difficult to treat and to detect in early stages by the traditional microbiol. analyses. The detn. of the chem. compn. of the extracellular polymeric substances (EPS) of the biofilm matrix, as well as the elucidation of the sensitivity of biofilms to enzymic degrdn. should facilitate the development of new therapies against biofilm-related infections. The chem. analyses of EPS had shown qual. and quant. variations of their nature, depending on the strains and culture conditions. The poly-N-acetylglucosamine (PNAG) is considered the main component of staphylococcal biofilms. However, certain strains form biofilms without PNAG. In addn. to PNAG and proteins, extracellular teichoic acid was identified as a new component of the staphylococcal biofilms. The sensitivity of staphylococcal biofilms to enzymic treatments depended on their relative chem. compn., and a PNAG-degrading enzyme, in conjunction with proteases, could be an efficient soln. to eliminate the staphylococcal biofilms. A detection of specific 'antibiofilm' antibodies in the blood serum of patients could serve as a convenient noninvasive and inexpensive diagnostic tool for the detection of foreign body-assocd. staphylococcal infections. Used as a coating antigen in the ELISA test, PNAG did not sufficiently discriminate healthy individuals from the infected patients.
- 33Sadovskaya, I.; Chaignon, P.; Kogan, G.; Chokr, A.; Vinogradov, E.; Jabbouri, S. Carbohydrate-containing components of biofilms produced in vitro by some staphylococcal strains related to orthopaedic prosthesis infections. FEMS Immunol. Med. Microbiol. 2006, 47 (1), 75– 82, DOI: 10.1111/j.1574-695X.2006.00068.x33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlsFWhsLY%253D&md5=8f85249e24039bdb87ff47ed6548d892Carbohydrate-containing components of biofilms produced in vitro by some staphylococcal strains related to orthopedic prosthesis infectionsSadovskaya, Irina; Chaignon, Philippe; Kogan, Grigorij; Chokr, Ali; Vinogradov, Evgeny; Jabbouri, SaidFEMS Immunology and Medical Microbiology (2006), 47 (1), 75-82CODEN: FIMIEV; ISSN:0928-8244. (Blackwell Publishing Ltd.)The capacity of coagulase-neg. staphylococci to colonize implanted medical devices is generally attributed to their ability to produce biofilms. Biofilm of the model strain of Staphylococcus epidermidis RP62A was shown to contain two carbohydrate-contg. moieties, a linear poly-β-(1 → 6)-N-acetyl-D-glucosamine (PNAG) and teichoic acid. In the present study, the authors investigated several biofilm-producing staphylococci isolated from infected orthopedic implants and characterized the compn. of the lab.-grown biofilms using chem. anal. and 1H NMR spectroscopy. Extracellular teichoic acid was produced by all strains studied. Some of the clin. strains were shown to produce biofilms with compns. similar to that of the model strain, contg. a varying amt. of PNAG. The chem. structure of PNAG of the clin. strains was similar to that previously described for the model strains S. epidermidis RP62A and Staphylococcus aureus MN8m, differing only in the amt. of charged groups. Biofilms of the strains producing a substantial amt. of PNAG were detached by dispersin B, a PNAG-degrading enzyme, while being unsusceptible to proteinase K treatment. On the other hand, some strains produced biofilms without any detectable amt. of PNAG. The biofilms of these strains were dispersed by proteinase K, but not by dispersin B.
- 34Kogan, G.; Sadovskaya, I.; Chaignon, P.; Chokr, A.; Jabbouri, S. Biofilms of clinical strains of Staphylococcus that do not contain polysaccharide intercellular adhesin. FEMS Microbiol. Lett. 2006, 255 (1), 11– 6, DOI: 10.1111/j.1574-6968.2005.00043.x34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjsVyrtbo%253D&md5=703e008c2fd50868538ea45d8289cd01Biofilms of clinical strains of Staphylococcus that do not contain polysaccharide intercellular adhesinKogan, Grigorij; Sadovskaya, Irina; Chaignon, Philippe; Chokr, Ali; Jabbouri, SaidFEMS Microbiology Letters (2006), 255 (1), 11-16CODEN: FMLED7; ISSN:0378-1097. (Blackwell Publishing Ltd.)Staphylococcus aureus and coagulase-neg. staphylococci, primarily Staphylococcus epidermidis, are recognized as a major cause of nosocomial infections assocd. with the use of implanted medical devices. The capacity of S. epidermidis to form biofilms, allowing it to evade host immune defense mechanisms and antibiotic therapy, is considered to be crucial in colonizing the surfaces of medical implants and dissemination of infection. It has previously been demonstrated that the biofilm of a model strain S. epidermidis RP62A comprises two carbohydrate-contg. moieties, a polysaccharide having a structure of a linear poly-N-acetyl-(1 → 6)-β-D-glucosamine and teichoic acid. Here, the authors show that, unlike this model strain, certain clin. isolates of coagulase-neg. staphylococci produce biofilms that do not contain detectable amts. of poly-N-acetyl-(1 → 6)-β-D-glucosamine. In contrast to that of S. epidermidis RP62A, these biofilms are not detached with metaperiodate, while proteinase K causes their partial dispersal.
- 35Warshakoon, H. J.; Burns, M. R.; David, S. A. Structure-activity relationships of antimicrobial and lipoteichoic acid-sequestering properties in polyamine sulfonamides. Antimicrob. Agents Chemother. 2009, 53 (1), 57– 62, DOI: 10.1128/AAC.00812-0835https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1Kksr0%253D&md5=d103ce5456e8b391e1bacf3df8c98849Structure-activity relationships of antimicrobial and lipoteichoic acid-sequestering properties in polyamine sulfonamidesWarshakoon, Hemamali J.; Burns, Mark R.; David, Sunil A.Antimicrobial Agents and Chemotherapy (2009), 53 (1), 57-62CODEN: AMACCQ; ISSN:0066-4804. (American Society for Microbiology)We have recently confirmed that lipoteichoic acid (LTA), a major constituent of the gram-pos. bacterial surface, is the endotoxin of gram-pos. bacteria that induces proinflammatory mols. in a Toll-like receptor 2 (TLR2)-dependent manner. LTA is an anionic amphipath whose physicochem. properties are similar to those of lipopolysaccharide (LPS), which is found on the outer leaflet of the outer membranes of gram-neg. organisms. Hypothesizing that compds. that sequester LPS could also bind to and inhibit LTA-induced cellular activation, we screened congeneric series of polyamine sulfonamides which we had previously shown effectively neutralized LPS both in vitro and in animal models of endotoxemia. We obsd. that these compds. do bind to and neutralize LTA, as reflected by the inhibition of TLR2-mediated NF-κB induction in reporter gene assays. Structure-activity studies showed a clear dependence of the acyl chain length on activity against LTA in compds. with spermine and homospermine scaffolds. We then sought to examine possible correlations between the neutralizing potency toward LTA and antimicrobial activity in Staphylococcus aureus. A linear relationship between LTA sequestration activity and antimicrobial activity for compds. with a spermine backbone was obsd., while all compds. with a homospermine backbone were equally active against S. aureus, regardless of their neutralizing potency toward LTA. These results suggest that the no. of protonatable charges is a key determinant of the activity toward the membranes of gram-pos. bacteria. The development of resistance to membrane-active antibiotics has been relatively slower than that to conventional antibiotics, and it is possible that compds. such as the acylpolyamines may be useful clin., provided that they have an acceptable safety profile and margin of safety. A more detailed understanding of the mechanisms of interactions of these compds. with LPS and LTA, as well as the gram-neg. and -pos. bacterial cell surfaces, will be instructive and should allow the rational design of analogs which combine antisepsis and antibacterial properties.
- 36Swoboda, J. G.; Campbell, J.; Meredith, T. C.; Walker, S. Wall teichoic acid function, biosynthesis, and inhibition. ChemBioChem 2010, 11 (1), 35– 45, DOI: 10.1002/cbic.20090055736https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1SqtLrE&md5=050008f52b07198ece482cccdf237b4fWall teichoic acid function, biosynthesis, and inhibitionSwoboda, Jonathan G.; Campbell, Jennifer; Meredith, Timothy C.; Walker, SuzanneChemBioChem (2010), 11 (1), 35-45CODEN: CBCHFX; ISSN:1439-4227. (Wiley-VCH Verlag GmbH & Co. KGaA)A review.
- 37Neuhaus, F. C.; Baddiley, J. A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteria. Microbiol. Mol. Biol. Rev. 2003, 67 (4), 686– 723, DOI: 10.1128/MMBR.67.4.686-723.200337https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmt1SqsA%253D%253D&md5=e47cfc2263faafd6fc8fd7a6671acf72A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteriaNeuhaus, Francis C.; Baddiley, JamesMicrobiology and Molecular Biology Reviews (2003), 67 (4), 686-723CODEN: MMBRF7; ISSN:1092-2172. (American Society for Microbiology)A review. Teichoic acids (TAs) are major wall and membrane components of most gram-pos. bacteria. With few exceptions, they are polymers of glycerol-phosphate or ribitol-phosphate to which are attached glycosyl and D-alanyl ester residues. Wall TA is attached to peptidoglycan via a linkage unit, whereas lipoteichoic acid is attached to glycolipid intercalated in the membrane. Together with peptidoglycan, these polymers make up a polyanionic matrix that functions in (1) cation homeostasis; (2) trafficking of ions, nutrients, proteins, and antibiotics; (3) regulation of autolysins; and (4) presentation of envelope proteins. The esterification of TAs with D-alanyl esters provides a means of modulating the net anionic charge, detg. the cationic binding capacity, and displaying cations in the wall. This review addresses the structures and functions of D-alanyl-TAs, the D-alanylation system encoded by the dlt operon, and the roles of TAs in cell growth. The importance of dlt in the physiol. of many organisms is illustrated by the variety of mutant phenotypes. In addn., advances in our understanding of D-alanyl ester function in virulence and host-mediated responses have been made possible through targeted mutagenesis of dlt. Studies of the mechanism of D-alanylation have identified two potential targets of antibacterial action and provided possible screening reactions for designing novel agents targeted to D-alanyl-TA synthesis.
- 38Martinic, M.; Hoare, A.; Contreras, I.; Alvarez, S. A. Contribution of the lipopolysaccharide to resistance of Shigella flexneri 2a to extreme acidity. PLoS One 2011, 6 (10), e25557, DOI: 10.1371/journal.pone.002555738https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlGmtL3I&md5=1c259a1c0872e2a7867a619599bd62faContribution of the lipopolysaccharide to resistance of Shigella flexneri 2a to extreme acidityMartinic, Mara; Hoare, Anilei; Contreras, Ines; Alvarez, Sergio A.PLoS One (2011), 6 (10), e25557CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)Shigella flexneri is endemic in most underdeveloped countries, causing diarrheal disease and dysentery among young children. In order to reach its target site, the colon, Shigella must overcome the acid environment of the stomach. Shigella is able to persist in this stressful environment and, because of this ability it can initiate infection following the ingestion of very small inocula. Thus, acid resistance is considered an important virulence trait of this bacterium. It was reported that moderate acid conditions regulate the expression of numerous components of the bacterial envelope. Because the lipopolysaccharide (LPS) is the major component of the bacterial surface, here we have addressed the role of LPS in acid resistance of S. flexneri 2a. Defined deletion mutants in genes encoding proteins involved in the synthesis, assembly and length regulation of the LPS O antigen were constructed and assayed for resistance to pH 2.5 after adaptation to pH 5.5. The results showed that a mutant lacking O antigen was significantly more sensitive to extreme acid conditions than the wild type. Not only the presence of polymd. O antigen, but also a particular polymer length (S-OAg) was required for acid resistance. Glucosylation of the O antigen also contributed to this property. In addn., a moderate acidic pH induced changes in the compn. of the lipid A domain of LPS. The main modification was the addn. of phosphoethanolamine to the 1' phosphate of lipid A. This modification increased resistance of S. flexneri to extreme acid conditions, provide that O antigen was produced. Overall, the results of this work point out to an important role of LPS in resistance of Shigella flexneri to acid stress.
- 39Brade, H.; Galanos, C. Isolation, purification, and chemical analysis of the lipopolysaccharide and lipid A of Acinetobacter calcoaceticus NCTC 10305. Eur. J. Biochem. 1982, 122 (2), 233– 7, DOI: 10.1111/j.1432-1033.1982.tb05871.x39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL38XpvFOgtQ%253D%253D&md5=b6ed534a884e06e334f0a6caff38a56fIsolation, purification, and chemical analysis of the lipopolysaccharide and lipid A of Acinetobacter calcoaceticus NCTC 10305Brade, Helmut; Galanos, ChrisEuropean Journal of Biochemistry (1982), 122 (2), 233-7CODEN: EJBCAI; ISSN:0014-2956.The lipopolysaccharide of A. calcoaceticus NCTC 10305 was obtained by a modified PhOH/CHCl3/light petroleum method from the bacterial cells and from the culture medium in yields of 1.6% and 2.2%, resp. (based on the bacterial dry wt.). On chem. anal., the prepns. proved to be identical. The lipopolysaccharide obtained from the cells was purified by repeated ultracentrifugation, electrodialysis, and pptn. with NaCl. It was free of nucleic acids, proteins, and glycans. In the anal. ultracentrifuge, the triethylamine and Na salt forms of the lipopolysaccharide showed a sedimentation coeff. of 8.9 S and 51 S, resp. The lipopolysaccharide consisted of glucosamine, 3-deoxy-D-manno-octulosonic acid, D-glucose, fatty acids, and phosphate in a molar ratio of 2:1:7:6:4. The fatty acids were predominantly lauric acid, 2-hydroxy, and 3-hydroxylauric acid in a molar ratio of 1:1:2. Only 3-hydroxylauric acid was found in amide linkage. On mild acid hydrolysis of the lipopolysaccharide, 65% lipid A were obtained, to which glucosamine was retained quant. It still contained 50% of the original glucose, whereas 1/3 of the liberated glucose was in monomeric form.
- 40Sutherland, I. Biofilm exopolysaccharides: a strong and sticky framework. Microbiology (London, U. K.) 2001, 147 (1), 3– 9, DOI: 10.1099/00221287-147-1-3There is no corresponding record for this reference.
- 41Duanis-Assaf, D.; Duanis-Assaf, T.; Zeng, G.; Meyer, R. L.; Reches, M.; Steinberg, D.; Shemesh, M. Cell wall associated protein TasA provides an initial binding component to extracellular polysaccharides in dual-species biofilm. Sci. Rep. 2018, 8 (1), 9350, DOI: 10.1038/s41598-018-27548-141https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1Mbpt1Kiuw%253D%253D&md5=aceb4fc30d8b3b8aedcd956f8b8c2b14Cell wall associated protein TasA provides an initial binding component to extracellular polysaccharides in dual-species biofilmDuanis-Assaf Danielle; Shemesh Moshe; Duanis-Assaf Danielle; Steinberg Doron; Duanis-Assaf Tal; Reches Meital; Zeng Guanghong; Meyer Rikke LouiseScientific reports (2018), 8 (1), 9350 ISSN:.Many bacteria in biofilm surround themselves by an extracellular matrix composed mainly of extracellular polysaccharide (EP), proteins such as amyloid-like fibers (ALF) and nucleic acids. While the importance of EP in attachment and acceleration of biofilm by a number of different bacterial species is well established, the contribution of ALF to attachment in multispecies biofilm remains unknown. The study presented here aimed to investigate the role of TasA, a precursor for ALF, in cell-cell interactions in dual-species biofilms of Bacillus subtilis and Streptococcus mutans. Expression of major B. subtilis matrix operons was significantly up-regulated in the presence of S. mutans during different stages of biofilm formation, suggesting that the two species interacted and modulated gene expression in each other. Wild-type B. subtilis expressing TasA adhered strongly to S. mutans biofilm, while a TasA-deficient mutant was less adhesive and consequently less abundant in the dual-species biofilm. Dextran, a biofilm polysaccharide, induced aggregation of B. subtilis and stimulated adhesion to S. mutans biofilms. This effect was only observed in the wild-type strain, suggesting that interactions between TasA and dextran-associated EP plays an important role in inter-species interactions during initial stages of multispecies biofilm development.
- 42Chandra, P.; Enespa; Singh, R.; Arora, P. K. Microbial lipases and their industrial applications: a comprehensive review. Microb. Cell Fact. 2020, 19, 169, DOI: 10.1186/s12934-020-01428-842https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhs1ygt7nL&md5=c0e49e9ac0a09ec8ab62bcc34200b932Microbial lipases and their industrial applications: a comprehensive reviewChandra, Prem; Enespa; Singh, Ranjan; Arora, Pankaj KumarMicrobial Cell Factories (2020), 19 (1), 169CODEN: MCFICT; ISSN:1475-2859. (BioMed Central Ltd.)A review. Lipases are very versatile enzymes, and produced the attention of the several industrial processes. Lipase can be achieved from several sources, animal, vegetable, and microbiol. The uses of microbial lipase market is estd. to be USD 425.0 Million in 2018 and it is projected to reach USD 590.2 Million by 2023, growing at a CAGR of 6.8% from 2018. Microbial lipases (EC 3.1.1.3) catalyze the hydrolysis of long chain triglycerides. The microbial origins of lipase enzymes are logically dynamic and proficient also have an extensive range of industrial uses with the manufg. of altered mols. The unique lipase (triacylglycerol acyl hydrolase) enzymes catalyzed the hydrolysis, esterification and alcoholysis reactions. Immobilization has made the use of microbial lipases accomplish its best performance and hence suitable for several reactions and need to enhance aroma to the immobilization processes. Immobilized enzymes depend on the immobilization technique and the carrier type. The choice of the carrier concerns usually the biocompatibility, chem. and thermal stability, and insoly. under reaction conditions, capability of easy rejuvenation and reusability, as well as cost proficiency. Bacillus spp., Achromobacter spp., Alcaligenes spp., Arthrobacter spp., Pseudomonos spp., of bacteria and Penicillium spp., Fusarium spp., Aspergillus spp., of fungi are screened large scale for lipase prodn. Lipases as multipurpose biol. catalyst has given a favorable vision in meeting the needs for several industries such as biodiesel, foods and drinks, leather, textile, detergents, pharmaceuticals and medicals. This review represents a discussion on microbial sources of lipases, immobilization methods increased productivity at market profitability and reduce logistical liability on the environment and user.
- 43Dully, M.; Brasnett, C.; Djeghader, A.; Seddon, A.; Neilan, J.; Murray, D.; Butler, J.; Soulimane, T.; Hudson, S. P. Modulating the release of pharmaceuticals from lipid cubic phases using a lipase inhibitor. J. Colloid Interface Sci. 2020, 573, 176– 192, DOI: 10.1016/j.jcis.2020.04.01543https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXmvVSntL4%253D&md5=0e5a45b15dc805d4cf579b6b7b6258eeModulating the release of pharmaceuticals from lipid cubic phases using a lipase inhibitorDully, Michele; Brasnett, Christopher; Djeghader, Ahmed; Seddon, Annela; Neilan, John; Murray, David; Butler, James; Soulimane, Tewfik; Hudson, Sarah P.Journal of Colloid and Interface Science (2020), 573 (), 176-192CODEN: JCISA5; ISSN:0021-9797. (Elsevier B.V.)Lipid cubic phase formulations have gained recognition as potential controlled delivery systems for a range of active pharmaceutical and biol. agents on account of their desirable physiochem. properties and ability to encapsulate both hydrophobic and hydrophilic mols. The most widely studied lipid cubic systems are those of the monoacylglycerol lipid family. These formulations are susceptible to lipolysis by a variety of enzymes, including lipases and esterases, which attack the ester bond present on the lipid chain bridging the oleic acid component to the glycerol backbone. The release of poorly sol. mols. residing in the lipid membrane portions of the phase is limited by the breakdown of the matrix; thus, presenting a potential means for further controlling and sustaining the release of therapeutic agents by targeting the matrix stability and its rate of degrdn. The aims of the present study were twofold: to evaluate an approach to regulate the rate of degrdn. of lipid cubic phase drug delivery systems by targeting the enzyme interactions responsible for their demise; and to study the subsequent drug release profiles from bulk lipid cubic gels using model drugs of contrasting hydrophobicity. Here, hybrid materials consisting of cubic phases with monoacylglycerol lipids of different chain lengths formulated with a potent lipase inhibitor tetrahydrolipstatin were designed. Modulation of the release of a hydrophobic model pharmaceutical, a clofazimine salt, was obtained by exploiting the matrixes' enzyme-driven digestion. A stable cubic phase is described, displaying controlled degrdn. with at least a 4-fold improvement compared to the blank systems shown in inhibitor-contg. cubic systems. Sustained release of the model hydrophobic pharmaceutical was studied over 30 days to highlight the advantage of incorporating an inhibitor into the cubic network to achieve tunable lipid release systems. This is done without neg. affecting the structure of the matrix itself, as shown by comprehensive small-angle x-ray scattering expts.
- 44Chen, M.; Wei, J.; Xie, S.; Tao, X.; Zhang, Z.; Ran, P.; Li, X. Bacterial biofilm destruction by size/surface charge-adaptive micelles. Nanoscale 2019, 11 (3), 1410– 1422, DOI: 10.1039/C8NR05575K44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisFyntbvI&md5=64da4f386aca2e3dd667dbe1eac85e1dBacterial biofilm destruction by size/surface charge-adaptive micellesChen, Maohua; Wei, Jiaojun; Xie, Songzhi; Tao, Xinyan; Zhang, Zhanlin; Ran, Pan; Li, XiaohongNanoscale (2019), 11 (3), 1410-1422CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Biofilms formed by pathogenic bacteria are one of the most important reasons for multidrug resistance. One of the major limitations in the biofilm treatment is the existence of intensive matrixes, which greatly block the diffusion of antimicrobial agents. In the current study, we designed poly(aspartamide)-derived micelles self-assembled from cationic copolymers with azithromycin-conjugated and pH-sensitive copolymers, followed by loading cis-aconityl-D-tyrosine (CA-Tyr) via electrostatic interactions. In response to the acidic microenvironment of the biofilm matrix, the hydrophilic transition of the pH-sensitive copolymers and the removal of CA-Tyr led to a sharp decrease in micelle size from 107 nm to 54 nm and a rapid shift in their zeta potential from -11.7 mV to +26.4 mV, which facilitated the penetration of the micelles into biofilms. The acid-labile release of D-tyrosine disintegrated the biofilm matrix, and the lipase-triggered release of azithromycin eradicated the bacteria in the biofilms. An in vitro test was performed on pre-established P. aeruginosa biofilms in microwells, while biofilms grown on catheters were surgically implanted in rats for in vivo evaluation. The results demonstrated the capabilities of the size/surface charge-adaptive micelles in the intensive infiltration in the biofilm matrix and spatiotemporal release of biofilm dispersion and antibacterial agents for the comprehensive treatment of biofilm-relevant infections.
- 45do Vale, A.; Cabanes, D.; Sousa, S. Bacterial Toxins as Pathogen Weapons Against Phagocytes. Front. Microbiol. 2016, 7, 42, DOI: 10.3389/fmicb.2016.0004245https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28jgt1ajug%253D%253D&md5=df73510cd5384092bc8537e89cf8d860Bacterial Toxins as Pathogen Weapons Against Phagocytesdo Vale Ana; Cabanes Didier; Sousa SandraFrontiers in microbiology (2016), 7 (), 42 ISSN:1664-302X.Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favor microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signaling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.
- 46Seilie, E. S.; Bubeck Wardenburg, J. Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity. Semin. Cell Dev. Biol. 2017, 72, 101– 116, DOI: 10.1016/j.semcdb.2017.04.00346https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXnt1CqsL4%253D&md5=6441357949f86fdad33c76e1a37f13d4Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexitySeilie, E. Sachiko; Bubeck Wardenburg, JulianeSeminars in Cell & Developmental Biology (2017), 72 (), 101-116CODEN: SCDBFX; ISSN:1084-9521. (Elsevier Ltd.)A review. Staphylococcus aureus is a prominent human pathogen capable of infecting a variety of host species and tissue sites. This versatility stems from the pathogen's ability to secrete diverse host-damaging virulence factors. Among these factors, the S. aureus pore-forming toxins (PFTs) α-toxin and the bicomponent leukocidins, have garnered much attention for their ability to lyse cells at low concns. and modulate disease severity. Although many of these toxins were discovered nearly a century ago, their host cell specificities have only been elucidated over the past five to six years, starting with the discovery of the eukaryotic receptor for α-toxin and rapidly followed by identification of the leukocidin receptors. The identification of these receptors has revealed the species- and cell type-specificity of toxin binding, and provided insight into non-lytic effects of PFT intoxication that contribute to disease pathogenesis.
- 47Kennedy, A. D.; Wardenburg, J. B.; Gardner, D. J.; Long, D.; Whitney, A. R.; Braughton, K. R.; Schneewind, O.; DeLeo, F. R. Targeting of alpha-hemolysin by active or passive immunization decreases severity of USA300 skin infection in a mouse model. J. Infect. Dis. 2010, 202 (7), 1050– 1058, DOI: 10.1086/65604347https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3cjosVyktQ%253D%253D&md5=00c95ac9cdb4554b6ec183edd1d4a2cbTargeting of alpha-hemolysin by active or passive immunization decreases severity of USA300 skin infection in a mouse modelKennedy Adam D; Bubeck Wardenburg Juliane; Gardner Donald J; Long Daniel; Whitney Adeline R; Braughton Kevin R; Schneewind Olaf; DeLeo Frank RThe Journal of infectious diseases (2010), 202 (7), 1050-8 ISSN:.Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are predominantly those affecting skin and soft tissues. Although progress has been made, our knowledge of the molecules that contribute to the pathogenesis of CA-MRSA skin infections is incomplete. We tested the hypothesis that alpha-hemolysin (Hla) contributes to the severity of USA300 skin infections in mice and determined whether vaccination against Hla reduces disease severity. Isogenic hla-negative (Deltahla) strains caused skin lesions in a mouse infection model that were significantly smaller than those caused by wild-type USA300 and Newman strains. Moreover, infection due to wild-type strains produced dermonecrotic skin lesions, whereas there was little or no dermonecrosis in mice infected with Deltahla strains. Passive immunization with Hla-specific antisera or active immunization with a nontoxigenic form of Hla significantly reduced the size of skin lesions caused by USA300 and prevented dermonecrosis. We conclude that Hla is a potential target for therapeutics or vaccines designed to moderate severe S. aureus skin infections.
- 48Fang, R. H.; Luk, B. T.; Hu, C. M.; Zhang, L. Engineered nanoparticles mimicking cell membranes for toxin neutralization. Adv. Drug Delivery Rev. 2015, 90, 69– 80, DOI: 10.1016/j.addr.2015.04.00148https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXms1Wqs7k%253D&md5=3e5830a5084e6e23f503ebbad29db975Engineered nanoparticles mimicking cell membranes for toxin neutralizationFang, Ronnie H.; Luk, Brian T.; Hu, Che-Ming J.; Zhang, LiangfangAdvanced Drug Delivery Reviews (2015), 90 (), 69-80CODEN: ADDREP; ISSN:0169-409X. (Elsevier B.V.)Protein toxins secreted from pathogenic bacteria and venomous animals rely on multiple mechanisms to overcome the cell membrane barrier to inflict their virulence effect. A promising therapeutic concept toward developing a broadly applicable anti-toxin platform is to administer cell membrane mimics as decoys to sequester these virulence factors. As such, lipid membrane-based nanoparticulates are an ideal candidate given their structural similarity to cellular membranes. This article reviews the virulence mechanisms employed by toxins at the cell membrane interface and highlights the application of cell-membrane mimicking nanoparticles as toxin decoys for systemic detoxification. In addn., the implication of particle/toxin nanocomplexes in the development of toxoid vaccines is discussed.
- 49Vandenesch, F.; Lina, G.; Henry, T. Staphylococcus aureus hemolysins, bi-component leukocidins, and cytolytic peptides: a redundant arsenal of membrane-damaging virulence factors?. Front. Cell. Infect. Microbiol. 2012, 2, 12, DOI: 10.3389/fcimb.2012.0001249https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38bgvF2gsQ%253D%253D&md5=7ad8a181cfcf882127f26514b7d492c2Staphylococcus aureus hemolysins, bi-component leukocidins, and cytolytic peptides: a redundant arsenal of membrane-damaging virulence factors?Vandenesch Francois; Lina G; Henry ThomasFrontiers in cellular and infection microbiology (2012), 2 (), 12 ISSN:.One key aspect of the virulence of Staphylococcus aureus lies in its ability to target the host cell membrane with a large number of membrane-damaging toxins and peptides. In this review, we describe the hemolysins, the bi-component leukocidins (which include the Panton Valentine leukocidin, LukAB/GH, and LukED), and the cytolytic peptides (phenol soluble modulins). While at first glance, all of these factors might appear redundant, it is now clear that some of these factors play specific roles in certain S. aureus life stages and diseases or target specific cell types or species. In this review, we present an update of the literature on toxin receptors and their cell type and species specificities. Furthermore, we review epidemiological studies and animal models illustrating the role of these membrane-damaging factors in various diseases. Finally, we emphasize the interplay of these factors with the host immune system and highlight all their non-lytic functions.
- 50Perera, R. T.; Fleming, A. M.; Peterson, A. M.; Heemstra, J. M.; Burrows, C. J.; White, H. S. Unzipping of A-Form DNA-RNA, A-Form DNA-PNA, and B-Form DNA-DNA in the alpha-Hemolysin Nanopore. Biophys. J. 2016, 110 (2), 306– 314, DOI: 10.1016/j.bpj.2015.11.02050https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVeisrnF&md5=a83375c82b0d649d140f24db51ee265bUnzipping of A-Form DNA-RNA, A-Form DNA-PNA, and B-Form DNA-DNA in the α-Hemolysin NanoporePerera, Rukshan T.; Fleming, Aaron M.; Peterson, Amberlyn M.; Heemstra, Jennifer M.; Burrows, Cynthia J.; White, Henry S.Biophysical Journal (2016), 110 (2), 306-314CODEN: BIOJAU; ISSN:0006-3495. (Cell Press)Unzipping of double-stranded nucleic acids by an elec. field applied across a wild-type α-hemolysin (αHL) nanopore provides structural information about different duplex forms. Comparative studies on A-form DNA-RNA duplexes and B-form DNA-DNA duplexes with a single-stranded tail identified significant differences in the blockage current and the unzipping duration between the two helical forms. The B-form duplex blocks the channel 1.9 ± 0.2 pA more and unzips ∼15-fold more slowly than an A-form duplex at 120 mV. The authors developed a model to describe the dependence of duplex unzipping on structure. The wider A-form duplex (d = 2.4 nm) is unable to enter the vestibule opening of αHL on the cis side, leading to unzipping outside of the nanopore with higher residual current and faster unzipping times. In contrast, the smaller B-form duplexes (d = 2.0 nm) enter the vestibule of αHL, resulting in decreased current blockages and slower unzipping. The authors studied the effects of varying the length of the single-stranded overhang, and studied A-form DNA-PNA duplexes to provide addnl. support for the proposed model. This study identifies key differences between A- and B-form duplex unzipping that will be important in the design of future probe-based methods for detecting DNA or RNA.
- 51Sanjay, S. T.; Zhou, W.; Dou, M.; Tavakoli, H.; Ma, L.; Xu, F.; Li, X. Recent advances of controlled drug delivery using microfluidic platforms. Adv. Drug Delivery Rev. 2018, 128, 3– 28, DOI: 10.1016/j.addr.2017.09.01351https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1Sqtr3O&md5=64c40e947a71171c4e9630ef3b4e3330Recent advances of controlled drug delivery using microfluidic platformsSanjay, Sharma T.; Zhou, Wan; Dou, Maowei; Tavakoli, Hamed; Ma, Lei; Xu, Feng; Li, XiuJunAdvanced Drug Delivery Reviews (2018), 128 (), 3-28CODEN: ADDREP; ISSN:0169-409X. (Elsevier B.V.)Conventional systematically-administered drugs distribute evenly throughout the body, get degraded and excreted rapidly while crossing many biol. barriers, leaving min. amts. of the drugs at pathol. sites. Controlled drug delivery aims to deliver drugs to the target sites at desired rates and time, thus enhancing the drug efficacy, pharmacokinetics, and bioavailability while maintaining minimal side effects. Due to a no. of unique advantages of the recent microfluidic lab-on-a-chip technol., microfluidic lab-on-a-chip has provided unprecedented opportunities for controlled drug delivery. Drugs can be efficiently delivered to the target sites at desired rates in a well-controlled manner by microfluidic platforms via integration, implantation, localization, automation, and precise control of various microdevice parameters. These features accordingly make reproducible, on-demand, and tunable drug delivery become feasible. On-demand self-tuning dynamic drug delivery systems have shown great potential for personalized drug delivery. This review presents an overview of recent advances in controlled drug delivery using microfluidic platforms. The review first briefly introduces microfabrication techniques of microfluidic platforms, followed by detailed descriptions of numerous microfluidic drug delivery systems that have significantly advanced the field of controlled drug delivery. Those microfluidic systems can be sepd. into four major categories, namely drug carrier-free micro-reservoirbased drug delivery systems, highly integrated carrier-freemicrofluidic lab-on-a-chip systems, drug carrier-integrated microfluidic systems, and microneedles. Microneedles can be further categorized into five different types, i.e. solid, porous, hollow, coated, and biodegradable microneedles, for controlled transdermal drug delivery. At the end, we discuss current limitations and future prospects of microfluidic platforms for controlled drug delivery.
- 52Hurlow, J.; Couch, K.; Laforet, K.; Bolton, L.; Metcalf, D.; Bowler, P. Clinical Biofilms: A Challenging Frontier in Wound Care. Adv. Wound Care (New Rochelle) 2015, 4 (5), 295– 301, DOI: 10.1089/wound.2014.056752https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1c%252FgsVGlsw%253D%253D&md5=4947b0135968dd623d057517e783b331Clinical Biofilms: A Challenging Frontier in Wound CareHurlow Jennifer; Couch Kara; Laforet Karen; Bolton Laura; Metcalf Daniel; Bowler PhilAdvances in wound care (2015), 4 (5), 295-301 ISSN:2162-1918.Significance: Biofilms have been implicated in a variety of wound complications. Recent Advances: Research has confirmed that biofilms form in wounds of patients experiencing delayed healing and may be a precursor to infection. Critical Issues: Research into the strength of this association is still in its infancy. Is biofilm formation a cause of these complications, a step toward them, or a signal that unresolved factors injuring tissue or delaying healing are setting the stage for biofilm formation, infection, and healing delay? To qualify biofilms for use in informing clinical practice decisions, biofilm characteristics supporting those decisions need standardized definitions and valid evidence that they predict or diagnose healing or infection outcomes. Literature searches of relevant terms reviewed biofilm definitions and validation of their role in predicting and diagnosing delayed wound healing or infection. Future Directions: Further research is needed to provide a rapid accurate technique to identify and characterize biofilms in ways that optimize their validity in diagnosing or screening patient risk of infection or delayed healing and to inform clinical decisions. This research will help validate biofilm's capacity to support wound care clinical practice decisions and establish their importance in guiding clinical practice.
- 53Schwartz, J. A.; Goss, S. G.; Facchin, F.; Avdagic, E.; Lantis, J. C. Surgical debridement alone does not adequately reduce planktonic bioburden in chronic lower extremity wounds. J. Wound Care 2014, 23 (Sup9), S4– S13, DOI: 10.12968/jowc.2014.23.Sup9.S4There is no corresponding record for this reference.
- 54Kaiser, P.; Wachter, J.; Windbergs, M. Therapy of infected wounds: overcoming clinical challenges by advanced drug delivery systems. Drug Delivery Transl. Res. 2021, 11 (4), 1545– 1567, DOI: 10.1007/s13346-021-00932-754https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXkvVaksLo%253D&md5=1d715c921b4de0774e1923a3ff80ec7eTherapy of infected wounds: overcoming clinical challenges by advanced drug delivery systemsKaiser, Pia; Waechter, Jana; Windbergs, MaikeDrug Delivery and Translational Research (2021), 11 (4), 1545-1567CODEN: DDTRCY; ISSN:2190-3948. (Springer)In recent years, the incidence of infected wounds is steadily increasing, and so is the clin. as well as economic interest in effective therapies. These combine redn. of pathogen load in the wound with general wound management to facilitate the healing process. The success of current therapies is challenged by harsh conditions in the wound microenvironment, chronicity, and biofilm formation, thus impeding adequate concns. of active antimicrobials at the site of infection. Inadequate dosing accuracy of systemically and topically applied antibiotics is prone to promote development of antibiotic resistance, while in the case of antiseptics, cytotoxicity is a major problem. Advanced drug delivery systems have the potential to enable the tailor-made application of antimicrobials to the side of action, resulting in an effective treatment with negligible side effects. This review provides a comprehensive overview of the current state of treatment options for the therapy of infected wounds. In this context, a special focus is set on delivery systems for antimicrobials ranging from semi-solid and liq. formulations over wound dressings to more advanced carriers such as nano-sized particulate systems, vesicular systems, electrospun fibers, and microneedles, which are discussed regarding their potential for effective therapy of wound infections. Further, established and novel models and anal. techniques for preclin. testing are introduced and a future perspective is provided.
- 55Srivastava, G. K.; Alonso-Alonso, M. L.; Fernandez-Bueno, I.; Garcia-Gutierrez, M. T.; Rull, F.; Medina, J.; Coco, R. M.; Pastor, J. C. Comparison between direct contact and extract exposure methods for PFO cytotoxicity evaluation. Sci. Rep. 2018, 8, 1425, DOI: 10.1038/s41598-018-19428-555https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MvjsFGnsw%253D%253D&md5=fa90084693e6d7061183b94cb6b1d8a1Comparison between direct contact and extract exposure methods for PFO cytotoxicity evaluationSrivastava Girish K; Alonso-Alonso Maria L; Fernandez-Bueno Ivan; Garcia-Gutierrez Maria T; Coco Rosa M; Pastor J Carlos; Srivastava Girish K; Fernandez-Bueno Ivan; Pastor J Carlos; Srivastava Girish K; Fernandez-Bueno Ivan; Coco Rosa M; Pastor J Carlos; Garcia-Gutierrez Maria T; Rull Fernando; Medina Jesus; Pastor J CarlosScientific reports (2018), 8 (1), 1425 ISSN:.A series of recent acute blindness cases following non-complicated retinal detachment surgery caused the release of several health alerts in Spain. The blindness was attributed to certain lots of perfluoro-octane (PFO; a volatile and transient medical device). Similar cases have been reported in other countries. This has raised questions regarding the validity of cytotoxicity test methods currently used to certify the safety of PFO lots. The tests were performed according to the International Organization for Standardization (ISO) norms, using the extract dilution method or the indirect contact method as applied to L929 cells, a line derived from mouse fibroblasts. The limitations of those methods have been resolved in this study by proposing a new cytotoxicity test method for volatile substances. The new method requires direct contact of the tested substance with cells that are similar to those exposed to the substance in the clinical setting. This approach includes a few new technical steps that are crucial for detecting cytotoxicity. Our new method detected toxic PFO lots that corresponded to the lots producing clinical blindness, which previous methods failed to detect. The study suggests applying this new method to avoid occurrence of such cases of blindness.
- 56Ternullo, S.; Basnet, P.; Holsaeter, A. M.; Flaten, G. E.; de Weerd, L.; Skalko-Basnet, N. Deformable liposomes for skin therapy with human epidermal growth factor: The effect of liposomal surface charge. Eur. J. Pharm. Sci. 2018, 125, 163– 171, DOI: 10.1016/j.ejps.2018.10.00556https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvV2gsbzI&md5=328c616541ac5184d1cd2948d67b0005Deformable liposomes for skin therapy with human epidermal growth factor: The effect of liposomal surface chargeTernullo, Selenia; Basnet, Purusotam; Holsaeter, Ann Mari; Flaten, Goeril Eide; de Weerd, Louis; Skalko-Basnet, NatasaEuropean Journal of Pharmaceutical Sciences (2018), 125 (), 163-171CODEN: EPSCED; ISSN:0928-0987. (Elsevier B.V.)The topical administration of exogenous human epidermal growth factor (hEGF) is a promising approach for improved chronic wound therapy. To develop therapeutically superior hEGF formulation, we prepd. hEGF-contg. neutral (NDLs), cationic (CDLs) and anionic (ADLs) deformable liposomes (DLs), resp., since it is expected that the liposomal surface charge can affect both the liposomal physicochem. properties, their skin penetration potential and therapeutic efficacy of liposome-assocd. drug. Among the studied DLs, ADLs were found to be most promising for sustained release of hEGF, as assessed in vitro using the polyamide membrane. Ex vivo studies revealed that all DLs were excellent systems for skin therapy with hEGF and no penetration of hEGF through the full thickness human skin was detected. ADLs provided a depot exhibiting the highest hEGF retention onto the human skin surface. ADLs also revealed enhanced mitogenic activities in human fibroblasts compared to both NDLs and CDLs after 48 h treatment. Moreover, hEGF-contg. ADLs significantly enhanced mitogenic activity in fibroblast as compared to activity of hEGF soln. (pos. control). Similar trends were obsd. in human keratinocytes after 24 h of treatment. We proved that the liposomal surface charge affects the therapeutic potential of hEGF-contg. liposomes. hEGF-contg. ADLs can be a promising nanosystem-based formulation for localized therapy of chronic wounds.
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Size distribution of PD 95/5, PDM 90/5/5, PDC 90/5/5, PDC 85/5/10; size distribution at physiological pH for PDM 90/5/5 and PDC 90/5/5 over 24 h; effect of formulations on fluorescent LPS at physiological and acidic pH; biofilm biomass quantification after treatment with the PDM 90/5/5 formulation (PDF)
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