In Situ Cross-Linking of Stimuli-Responsive Hemicellulose Microgels during Spray Drying
- Weifeng Zhao ,
- Robertus Wahyu N. Nugroho ,
- Karin Odelius ,
- Ulrica Edlund ,
- Changsheng Zhao , and
- Ann-Christine Albertsson
Abstract

Chemical cross-linking during spray drying offers the potential for green fabrication of microgels with a rapid stimuli response and good blood compatibility and provides a platform for stimuli-responsive hemicellulose microgels (SRHMGs). The cross-linking reaction occurs rapidly in situ at elevated temperature during spray drying, enabling the production of microgels in a large scale within a few minutes. The SRHMGs with an average size range of ∼1–4 μm contain O-acetyl-galactoglucomannan as a matrix and poly(acrylic acid), aniline pentamer (AP), and iron as functional additives, which are responsive to external changes in pH, electrochemical stimuli, magnetic field, or dual-stimuli. The surface morphologies, chemical compositions, charge, pH, and mechanical properties of these smart microgels were evaluated using scanning electron microscopy, IR, zeta potential measurements, pH evaluation, and quantitative nanomechanical mapping, respectively. Different oxidation states were observed when AP was introduced, as confirmed by UV spectroscopy and cyclic voltammetry. Systematic blood compatibility evaluations revealed that the SRHMGs have good blood compatibility. This bottom-up strategy to synthesize SRHMGs enables a new route to the production of smart microgels for biomedical applications.
1 Introduction
2 Experimental Section
2.1 Materials
2.2 Methods
Fabricating Microgels
| name | aspirator degree (%) | inlet temperature (°C) | outlet temperature (°C) | gas flow (mL/min) | pump (%) |
|---|---|---|---|---|---|
| H40 | 100 | 185 ± 3 | 85 ± 2 | 45 | 10 |
| H40AP16 | 100 | 185 ± 2 | 85 ± 4 | 35 | 10 |
| H40PAA8 | 100 | 185 ± 3 | 85 ± 3 | 45 | 10 |
| H40Fe16 | 100 | 185 ± 2 | 85 ± 3 | 45 | 10 |
| H40AP8PAA4 | 100 | 200 ± 3 | 100 ± 4 | 45 | 10 |
Scanning Electron Microscope
Fourier Transform Infrared
Thermogravimetric Analysis
UV–vis Tests
Cyclic Voltammetry
Zeta Potential Measurements
Swelling Ratio Measurements
(1)Vibrating Sample Magnetometer
Atomic Force Microscopy
(2)
(3)where a, δ, F, R, W, and Etot are tip–sample contact radius, deformation, adhesion force, tip radius, work of adhesion per unit area, and the reduced Young’s modulus, respectively.Clotting Time
Hemolysis Test
(4)Whole Blood Clotting Time
3 Results and Discussion
3.1 Microgel Synthesis
| name | function | AcGGM (mg) | functional materials (mg) | NaOH (mg) | ECH (mg) | H2O (mL) | |
|---|---|---|---|---|---|---|---|
| H40 | No | 1200 | 0 | 1200 | 1440 | 30 | |
| H40AP16 | electroactivity | 1200 | AP | 480 | 1200 | 1440 | 30 |
| H40PAA8 | pH response | 1200 | PAA | 240 | 1200 | 1440 | 30 |
| H40Fe16 | magnetism | 1200 | Fe powder | 480 | 1200 | 1440 | 30 |
| H40AP8PAA4 | dual-function | 1200 | AP/PAA | 240/120 | 1200 | 1440 | 30 |
Scheme 1

Figure 1

Figure 1. Freshly prepared SRHMGs (a-1, b-1, c-1, d-1, and e-1), SEM images (a-2, b-2, c-2, d-2, and e-2) and size distribution (a-3, b-3, c-3, d-3, and e-3) of H40 (a-1, a-2, and a-3), H40AP16 (b-1, b-2, and b-3), H40PAA8 (c-1, c-2, and c-3), H40Fe16 (d-1, d-2, and d-3), and H40AP8PAA4 (e-1, e-2, and e-3).
3.2 Electroactivity of the Microgels
Figure 2

Figure 2. UV–vis spectra of H40AP16 (a) and H40AP8PAA4 (b) in different pH aqueous buffer solutions. Images of H40AP16 (c) and H40AP8PAA4 (d) in different pH aqueous buffer solutions. Cyclic voltammograms of H40AP16 (e) and H40AP8PAA4 (f) in DMSO doped with three drops of 2 M HCl solution.
3.3 Microgel pH Sensitivity
Figure 3

Figure 3. Equilibrium swelling ratio of the SRHMGs under repeated pH changes between 7.4 and 2.2 (a). Zeta potential of the SRHMGs (b).
3.4 Microgel Magnetic Response
Figure 4

Figure 4. Photos of SRHMGs (H40Fe16) in a magnetic field: solid powder state (left); 10 mg/mL in water with a magnet field supplied at the bottom of the vial (middle); 10 mg/mL in water with a magnet field supplied at left side of the vial (right).
Figure 5

Figure 5. Magnetic hysteresis of H40Fe16 (a), EDS spectrum of H40Fe16 (b), and EDS spectrum of H40 (c) microgels.
3.5 Microgel Mechanical Properties
Figure 6

Figure 6. Young’s moduli of the SRHMGs measured using QNM: H40 (a), H40AP16 (b), H40PAA8 (c), H40Fe16 (d), and H40AP8PAA4 (e). (f) The surface roughness of these microgels.
3.6 Microgel Blood Compatibility
Figure 7

Figure 7. Blood compatibility measurements for the SRHMGs: (a) whole blood clotting time, (b) hemolysis, (c) activated partial thromboplastin time, and (d) thrombin time. Values are expressed as the mean ± standard deviation for n = 3.
Scheme 2

4 Conclusions
Supporting Information
The images, IR spectra, and TGA curves of stimuli-responsive hemicellulose microgels, proposed mechanism for the HCl doping of the electroactive hemicellulose microgels, cyclic voltammograms of AP in DMSO doped by three drops of 2 M HCl solution, molecular structure of AP segment in the microgels at various oxidation states. This material is available free of charge via the Internet at http://pubs.acs.org.
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.
Acknowledgment
The authors are grateful to the China Scholarship Council, the ERC Advanced Grant, PARADIGM (Grant No. 246776), the Major Program of the National Natural Science Foundation of China (Grant No. 51433007), and the Royal Institute of Technology (KTH) for financial support of this work. Dr. H. Lu at the Dept of Applied Electrochemistry, School of Chemical Science in KTH is thanked for the kind support in the cyclic voltammetry testing. Mr. C. He at the College of Polymer Science and Engineering, Sichuan University, is thanked for his generous help in the blood compatibility measurements.
References
This article references 59 other publications.
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], [CAS], Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XkvVKnu7k%253D&md5=4e799a90dd2db31d6bac66c66876afceCation-Condensed Microgel-Core Star Polymers as Polycationic Nanocapsules for Molecular Capture and Release in WaterFukae, Kaoru; Terashima, Takaya; Sawamoto, MitsuoMacromolecules (Washington, DC, United States) (2012), 45 (8), 3377-3386CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Cation-condensed microgel-core star polymers with poly(ethylene glycol) (PEG)-based arms were designed as unimol. polycationic nanocapsules (hosts) to encapsulate and stimuli-responsively release hydrophilic and anionic dyes (guests) in water. Typically, a cation-condensed star polymer (core cations: ∼670/star) was directly synthesized in high yield (>90%) by the linking reaction of a PEG macroinitiator (1) with a quaternary ammonium cation-carrying linking agent (2) in ruthenium-catalyzed living radical polymn. Analyzed by UV-vis spectroscopy, the star polymer efficiently encapsulated various hydrophilic dyes carrying sulfonate anions (methyl orange: MO; orange G: OG; methyl blue: MB) in water (UV-vis: ∼400 OG per a single star). The efficient dye encapsulation is due to the high concn. of quaternary ammonium cations in the core. The no. of core-bound dyes increased with increasing the no. of core-bound cations. The ligation structure of dyes within the core was proposed: the immobilization of one OG mol. involves two in-core ammonium cations. Addnl., stimuli-responsive release of dyes from cation-condensed star polymers was successfully achieved via ion exchange with NaCl aq. soln. - 20Gao, Y. F.; Serpe, M. J. Light-Induced Color Changes of Microgel-Based Etalons ACS Appl. Mater. Interfaces 2014, 6, 8461– 8466
- 21Yue, M.; Hoshino, Y.; Ohshiro, Y.; Imamura, K.; Miura, Y. Temperature-Responsive Microgel Films as Reversible Carbon Dioxide Absorbents in Wet Environment Angew. Chem., Int. Ed. 2014, 53, 2654– 2657Google ScholarThere is no corresponding record for this reference.
- 22Berger, S.; Zhang, H.; Pich, A. Microgel-Based Stimuli-Responsive Capsules Adv. Funct. Mater. 2009, 19, 554– 559Google ScholarThere is no corresponding record for this reference.
- 23Wong, J. E.; Gaharwar, A. K.; Mueller-Schulte, D.; Bahadur, D.; Richtering, W. Dual-Stimuli Responsive PNiPAM Microgel Achieved via Layer-by-Layer Assembly: Magnetic and Thermoresponsive J. Colloid Interface Sci. 2008, 324, 47– 54Google ScholarThere is no corresponding record for this reference.
- 24Hu, L.; Serpe, M. J. The Influence of Deposition Solution pH and Ionic Strength on the Quality of Poly(N-isopropylacrylamide) Microgel-Based Thin Films and Etalons ACS Appl. Mater. Interfaces 2013, 5, 11977– 11983
- 25Li, H.; Luo, R. M.; Lam, K. Y. Multiphysics Modeling of Electrochemomechanically Smart Microgels Responsive to Coupled pH/Electric Stimuli Macromol. Biosci. 2009, 9, 287– 297[Crossref], [PubMed], [CAS], Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjs1yhsr8%253D&md5=6072710ffaff67948503b18cd08202a5Multiphysics modeling of electrochemomechanically smart microgels responsive to coupled pH/electric stimuliLi, Hua; Luo, Rongmo; Lam, Khin YongMacromolecular Bioscience (2009), 9 (3), 287-297CODEN: MBAIBU; ISSN:1616-5187. (Wiley-VCH Verlag GmbH & Co. KGaA)A multiphysics model is developed to simulate the responsive behavior of smart pH-/elec.-sensitive hydrogels when immersed into pH buffer soln. and subjected to an externally applied elec. field, which is termed the MECpHe model. Comparison with exptl. data shows the MECpHe model to be accurate and stable. The influence of the externally applied elec. voltage is discussed with respect to the distribution of diffusive ionic species and the displacement of the hydrogel strip. The influences of initial charge d. and ionic strength on the swelling ratio and the bending deformation of the microgel strip are studied.
- 26Bian, S. S.; Zheng, J.; Yang, W. L. Dual Stimuli-Responsive Microgels Based on Photolabile Crosslinker: Temperature Sensitivity and Light-Induced Degradation J. Polym. Sci., Polym. Chem. 2014, 52, 1676– 1685[Crossref], [CAS], Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXks12mt70%253D&md5=7139a729c440560b6989bf0fbcd3b6a8Dual stimuli-responsive microgels based on photolabile crosslinker: Temperature sensitivity and light-induced degradationBian, Shanshan; Zheng, Jin; Yang, WuliJournal of Polymer Science, Part A: Polymer Chemistry (2014), 52 (12), 1676-1685CODEN: JPACEC; ISSN:0887-624X. (John Wiley & Sons, Inc.)The synthesis and characterization of a new photocleavable crosslinker is presented here. Dual stimuli-responsive P(VCL-co-NHMA) microgels were prepd. by pptn. polymn. of vinylcaprolactam (VCL) with N-hydroxymethyl acrylamide (NHMA) and the new crosslinker. The microgels had distinct temp. sensitivity as obsd. in the case of PVCL-based particles and their vol. phase transition temp. (VPTT) shifted to higher temp. with increasing NHMA content. Photolytic degrdn. expts. were investigated by irradn. with UV light, which led to microgel disintegration caused by cleavage of the photolabile crosslinking points. The degrdn. behavior of the microgels was conducted with respect to degrdn. rates by means of the relative turbidity changes. Hence, the microgels could totally degrade into short linear polymers by UV light, thus representing a great potential as new light and temp. dual responsive nanoscale materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014.
- 27Shi, S.; Wang, Q.; Wang, T.; Ren, S.; Gao, Y.; Wang, N. Thermo-, pH-, and Light-Responsive Poly(N-isopropylacrylamide-co-methacrylic acid)-Au Hybrid Microgels Prepared by the in Situ Reduction Method Based on Au-Thiol Chemistry J. Phys. Chem. B 2014, 118, 7177– 7186
- 28Yuan, Z. C.; Wang, Y.; Chen, D. J. Preparation and Characterization of Thermo-, pH-, and Magnetic-Field-Responsive Organic/Inorganic Hybrid Microgels Based on Poly(ethylene glycol) J. Mater. Sci. 2014, 49, 3287– 3296[Crossref], [CAS], Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlequ7Y%253D&md5=bb349d2239bf3dfd8d4377d56ec52326Preparation and characterization of thermo-, pH-, and magnetic-field-responsive organic/inorganic hybrid microgels based on poly(ethylene glycol)Yuan, Zhicheng; Wang, Yang; Chen, DajunJournal of Materials Science (2014), 49 (8), 3287-3296CODEN: JMTSAS; ISSN:0022-2461. (Springer)Nanocomposite microgels are a new class of intelligent materials because of their fast response time, large surface area, and so on. In this study, we demonstrate a new kind of multiple stimulus-responsive org./inorg. hybrid microgels by combining dual stimuli-responsive poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol)methacrylate-co-acrylic acid) (PMOA) microgels with magnetic attapulgite/Fe3O4 (AT-Fe3O4) nanoparticles. AT-Fe3O4 nanoparticles were introduced into the dual-responsive (temp. and pH) PMOA microgels network by in situ polymn. The responsive behaviors, microstructures, and the interaction between AT-Fe3O4 and PMOA microgels matrix of the prepd. microgels were systematically characterized using field emission SEM, particle size and Zeta potential analyzer, vibrating sample magnetometer, and Fourier transform IR spectroscopy. The results showed that the AT-Fe3O4 nanoparticles dispersed well in the microgel matrix, and the nanoparticles could be stably present in PMOA without phase sepn. because of the hydrogen bond (H-bond) interactions between AT-Fe3O4 nanoparticles and PMOA matrix. In addn., the multifunctional AT-Fe3O4/PMOA nanocomposite microgels had both temp./pH sensitivity and magnetic functionality.
- 29Polotsky, A. A.; Plamper, F. A.; Borisov, O. V. Collapse-to-Swelling Transitions in pH- and Thermoresponsive Microgels in Aqueous Dispersions: The Thermodynamic Theory Macromolecules 2013, 46, 8702– 8709[ACS Full Text
], [CAS], Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1GqurfE&md5=5212a53dd7dd0aafb4e76a255ac2f1ccCollapse-to-Swelling Transitions in pH- and Thermoresponsive Microgels in Aqueous Dispersions: The Thermodynamic TheoryPolotsky, Alexey A.; Plamper, Felix A.; Borisov, Oleg V.Macromolecules (Washington, DC, United States) (2013), 46 (21), 8702-8709CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)We present a theory of a conformational collapse-to-swelling transition that occurs in aq. dispersions of multiresponsive (pH- and thermoresponsive) microgels upon variation of ionic strength, temp., or pH. Our theory is based on osmotic balance arguments and explicitly accounts for ionization equil. inside microgel partices. The theory predicts complex patterns in the dependence of the microgel particle dimensions on the control parameters: An increase in temp. leads to worsening of the solvent quality for the gel forming LCST-polymers and to concomitant decrease in the dimensions of the gel particles. This collapse of the gel particles provoked by an increase in temp. occurs either smoothly (at high or low ionic strength), or may exhibit a jump-wise character at intermediate ionic strength. The theory further predicts that the degree of swelling of microgel particles varies nonmonotonously and exhibits a max. as a function of salt concn. at a pH close to the pK. This nonmonotonous variation of the particle dimensions occurs continuously at temps. below or slightly above LCST (good or marginal poor solvent strength conditions, resp.), whereas at higher temps. the jump-wise swelling of the gel particles is followed by either continuous or jump-wise collapse induced by progressive increase in the salt concn. A decrease/increase in pH leads to deswelling of the weak polyacid/polybase gel particles, which occurs smoothly at temps. below LCST, but may exhibit a discontinuity above LCST. These theor. predictions can be used for design of smart stimuli-responsive microgels. - 30Sollohub, K.; Cal, K. Spray Drying Technique: II. Current Applications in Pharmaceutical Technology J. Pharm. Sci. 2010, 99, 587– 597Google ScholarThere is no corresponding record for this reference.
- 31Vehring, R. Pharmaceutical Particle Engineering via Spray Drying Pharm. Res. 2008, 25, 999– 1022[Crossref], [PubMed], [CAS], Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXksFaiurs%253D&md5=f4762ce7b7fbc8ae4a984fb66e08d618Pharmaceutical Particle Engineering via Spray DryingVehring, ReinhardPharmaceutical Research (2008), 25 (5), 999-1022CODEN: PHREEB; ISSN:0724-8741. (Springer)A review. This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theor. framework for particle design calcns. It reviews exptl. research into parameters that influence particle formation. A classification based on dimensionless nos. is presented that can be used to est. how excipient properties in combination with process parameters influence the morphol. of the engineered particles. A wide range of pharmaceutical application examples-low d. particles, composite particles, microencapsulation, and glass stabilization-is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts.
- 32Esposito, E.; Roncarati, R.; Cortesi, R.; Cervellati, F.; Nastruzzi, C. Production of Eudragit Microparticles by Spray-Drying Technique: Influence of Experimental Parameters on Morphological and Dimensional Characteristics Pharm. Dev. Technol. 2000, 5, 267– 278Google ScholarThere is no corresponding record for this reference.
- 33De Smet, R.; Verschuere, S.; Allais, L.; Leclercq, G.; Dierendonck, M.; De Geest, B. G.; Van Driessche, I.; Demoor, T.; Cuvelier, C. A. Spray-Dried Polyelectrolyte Microparticles in Oral Antigen Delivery: Stability, Biocompatibility, and Cellular Uptake Biomacromolecules 2014, 15, 2301– 2309
- 34Ryberg, Y. Z.; Edlund, U.; Albertsson, A.-C. Innovative Approaches for Converting a Wood Hydrolysate to High-Quality Barrier Coatings ACS Appl. Mater. Interfaces 2013, 5, 7748– 7757Google ScholarThere is no corresponding record for this reference.
- 35Arias, V.; O, K.; Albertsson, A.-C. Nano-stereocomplexation of Polylactide (PLA) Spheres by Spray Droplet Atomization Macromol. Rapid Commun. 2014, 35, 1949– 1953Google ScholarThere is no corresponding record for this reference.
- 36Iwasaki, K. Production of a Functionally Graded Artificial Tooth Root by Unique Sequence of Processes Mater. Res. Innov. 1997, 1, 180– 187[Crossref], [CAS], Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXltFCksQ%253D%253D&md5=5e647b21731ce8decebd3d66b567daadProduction of a functionally graded artificial tooth root by unique sequence of processesIwasaki, KunihikoMaterials Research Innovations (1997), 1 (3), 180-187CODEN: MRINFV; ISSN:1432-8917. (Springer-Verlag)A unique sequence of processes is used to produce a prototype of a functionally graded artificial tooth root: (1) dry-jet spraying of the mixt. of Ti and Al2O3 ultrafine particles (UFPs) produced by radio-frequency plasma onto the surface of a cylindrical Ti rod, where the compn. of the UFPs is changed gradually in the outward radial direction from Ti to Al2O3; (2) temp.-gradient sintering of the deposited composite, where the Ti - and the Al2O3 - rich sides are heated simultaneously at about 1400 K and 1800 K, resp.; (3) plasma spray coating of hydroxyapatite (HAP) onto the outermost Al2O3 surface of the sintered composite. The final product has compressive strength of more than 200 MPa and is durable against fatigue test of 107 stress cycles at 1000 N. The adhesion strength between the Ti substrate and the Ti-Al2O3 functionally graded layer exceeds 65 MPa. No contamination with heavy metals is detected throughout the processes and biol. cell growth is confirmed to occur on the HAP surface. With these mech. and biochem. properties the composite produced here is considered to be highly suitable for an artificial tooth root. A series of processes developed here are expected to be applied to the prodn. of various kinds of fine-grained functionally graded materials with complicated forms.
- 37Schnieders, J.; Gbureck, U.; Germershaus, O.; Kratz, M.; Jones, D. B.; Kissel, T. Ex Vivo Human Trabecular Bone Model for Biocompatibility Evaluation of Calcium Phosphate Composites Modified with Spray Dried Biodegradable Microspheres Adv. Healthcare Mater. 2013, 2, 1361– 1369[Crossref], [PubMed], [CAS], Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsFOhurzO&md5=88b418802a44b716663ede45aa9984beEx Vivo Human Trabecular Bone Model for Biocompatibility Evaluation of Calcium Phosphate Composites Modified with Spray Dried Biodegradable MicrospheresSchnieders, Julia; Gbureck, Uwe; Germershaus, Oliver; Kratz, Marita; Jones, David B.; Kissel, ThomasAdvanced Healthcare Materials (2013), 2 (10), 1361-1369CODEN: AHMDBJ; ISSN:2192-2640. (Wiley-VCH Verlag GmbH & Co. KGaA)Our aim was to study the suitability of the ex-vivo human trabecular bone bioreactor ZetOS to test the biocompatibility of calcium phosphate bone cement composites modified with spray dried, drug loaded microspheres. We hypothesized, that this bone bioreactor could be a promising alternative to in vivo assessment of biocompatibility in living human bone over a defined time period. Composites consisting of tetracycline loaded poly(lactic-co-glycolic acid) microspheres and calcium phosphate bone cement, were inserted into in vitro cultured human femora head trabecular bone and incubated over 30 days at 37°C in the incubation system. Different biocompatibility parameters, such as lactate dehydrogenase activity, alk. phosphatase release and the expression of relevant cytokines, IL-1β, IL-6, and TNF-α, were measured in the incubation medium. No significant differences in alk. phosphatase, osteocalcin, and lactate dehydrogenase activity were measured compared to control samples. Tetracycline was released from the microspheres, delivered and incorporated into newly formed bone. In this study we demonstrated that ex vivo biocompatibility testing using human trabecular bone in a bioreactor is a potential alternative to animal expts. since bone metab. is still maintained in a physiol. environment ex vivo.
- 38Jacobs, A.; Dahlman, O. Characterization of The Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry Biomacromolecules 2001, 2, 894– 905[ACS Full Text
], [CAS], Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXkt1yru7k%253D&md5=dce8a603dd2a680e458452836b07f8d1Characterization of the molar masses of hemicelluloses from wood and pulps employing size exclusion chromatography and matrix-assisted laser desorption ionization time-of-flight mass spectrometryJacobs, Anna; Dahlman, OlofBiomacromolecules (2001), 2 (3), 894-905CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)The molar mass parameters for arabino-4-O-methylglucuronoxylans, arabinohexenuronoxylans, 4-O-methylglucuronoxylans, hexenuronoxylans, and galactoglucomannans extd. from wood and pulps were detd. To characterize different types of hemicellulose (I) samples, delignified wood (spruce, pine, larch, aspen, and birch) and chem. pulps (un-bleached and TCF-bleached) were extd. with DMSO or alk. aq. solns. SEC with off-line matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS) were employed to characterize the molar masses. The I exts. were sepd. by SEC into fractions, each contg. components with a narrow range of molar masses, and the av. molar mass of each fraction was subsequently detd. by MALDI-MS. The molar mass parameters for the I samples were then calcd. on the basis of the SEC distribution curves and MALDI-MS spectra. As expected, in most cases, the I samples extd. from wood (holocellulose) exhibited higher molar masses than did the corresponding I samples from chem. pulps. The molar mass parameters for I samples isolated from pulps derived from cooking samples of the same batch of softwood chips decreased in the following order: ASAM pulp > MSSAQ pulp > kraft pulp. The lowest molar masses were demonstrated by the glucuronoxylans extd. from pulps obtained by cooking with acidic sulfite. The xylan (II) samples from bleached kraft pulp were characterized by molar masses that were only slightly lower than those of the corresponding II samples from un-bleached pulp. The II samples extd. into DMSO exhibited somewhat lower molar masses than did the corresponding II samples extd. into alk. aq. solns. In all cases the range of molar masses demonstrated by the I samples investigated was shown to be rather narrow, i.e., the polydispersity index Mw/Mn was approx. 1.1-1.4. 6860-47-5 47592-59-6 188641-72-7 190194-13-9, (4ΔUA)-β-D-Xylopentaose 190194-14-0 190194-15-1, (4ΔUA)-β-D-Xylotetraose 190194-17-3 192331-90-1 192331-91-2 192331-92-3. - 39Huang, L.; Hu, J.; Lang, L.; Wang, X.; Zhang, P.; Jing, X.; Wang, X.; Chen, X.; Lelkes, P. I.; MacDiarmid, A. G.; Wei, Y. Synthesis and Characterization of Electroactive and Biodegradable ABA Block Copolymer of Polylactide and Aniline Pentamer Biomaterials 2007, 28, 1741– 1751Google ScholarThere is no corresponding record for this reference.
- 40Derjaguin, B. V.; Muller, V. M.; Toporov, Y. P. Effect of Contact Deformations on The Adhesion of Particles J. Colloid Interface Sci. 1975, 53, 314– 326[Crossref], [CAS], Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlGhtLrE&md5=b1cd96f05d5c46e2e72a3dcb947a8edcEffect of contact deformations on the adhesion of particlesDerjaguin, B. V.; Muller, V. M.; Toporov, Yu. P.Journal of Colloid and Interface Science (1975), 53 (2), 314-326CODEN: JCISA5; ISSN:0021-9797. (Academic Press, Inc.)A strict theory of reciprocal influence of the contact deformation and mol. attraction of a ball and a plane has been developed. It has been shown that despite the van der Waals' forces being capable of increasing the elastic contact area between the ball and the plane, the force that is required to overcome the mol. forces arising when the contact is broken does not increase thereby. In fact, it remains equal to the attraction force value that is detd. when considering the point contact of a nondeformed ball with a plane. In the absence of the electrostatic component, the adhesion force is equiv. to the first power of the ball radius and to the amt. of work per unit area as required for effecting the equil. tearing-off of a flat surface of the same nature.
- 41Zhou, H.; Cheng, C.; Qin, H.; Ma, L.; He, C.; Nie, S.; Zhang, X.; Fu, Q.; Zhao, C. Self-Assembled 3D Biocompatible and Bioactive Layer at the Macro-interface via Graphene-Based Supermolecules Polym. Chem. 2014, 5, 3563– 3575[Crossref], [CAS], Google Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXns1Wju70%253D&md5=254eec1c4193bd2067850a2dd92d4ab3Self-assembled 3D biocompatible and bioactive layer at the macro-interface via graphene-based supermoleculesZhou, Hongju; Cheng, Chong; Qin, Hui; Ma, Lang; He, Chao; Nie, Shengqiang; Zhang, Xiang; Fu, Qiang; Zhao, ChangshengPolymer Chemistry (2014), 5 (11), 3563-3575CODEN: PCOHC2; ISSN:1759-9962. (Royal Society of Chemistry)Research on the interface self-assembly of functional layers is fuelled by diverse biomedical needs, like drug encapsulation and release, stem cell proliferation and differentiation, cell and tissue cultures, as well as artificial organs. In this study, a novel and biocompatible 3D composite layer is fabricated on a membrane substrate by the layer-by-layer (LBL) self-assembly of graphene-based 2D supermols. The graphene-based 2D supermols. are prepd. by grafting poly(styrenesulfonate) (PSS, polyanion) and poly(acrylamide) (PAM, polycation) onto graphene oxide (GO) through free radical polymn. Then, the prepd. graphene-based supermols. are taken to construct a 3D porous thin film layer through a LBL process. Polyethersulfone (PES) membrane is chosen as the model substrate. The chem. compn., surface morphol., water contact angle, surface zeta-potential, blood compatibility and the cell compatibility are systematically investigated. The results indicate that the 2D graphene-based supermols. are successfully assembled into a 3D porous thin film layer structure on the membrane surface. The assembled layer shows increased hydrophilicity, suppressed platelet adhesion, and a limited hemolysis ratio and complement activation compared to the pristine substrate. The cell morphol. observation and cytotoxicity assays demonstrate that the 3D graphene layer shows superior performance both in endothelial and hepatocyte cells proliferation and morphol. differentiation. In addn., the excellent anticoagulant bioactivities indicate that the 2D graphene-based supermols. have heparin-mimicking biol. activity. In general, the protocol of interface thin film layer self-assembly confers the modified substrates with integrated blood compatibility, cell proliferation and biol. activity; which may forward the fabrication of multi-functional biomedical devices by the 2D graphene-based supermols.
- 42He, A.; Lei, B.; Cheng, C.; Li, S.; Ma, L.; Sun, S.; Zhao, C. Toward Safe, Efficient and Multifunctional 3D Blood-Contact Adsorbents Engineered by Biopolymers/Graphene Oxide Gels RSC Adv. 2013, 3, 22120– 22129[Crossref], [CAS], Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1Cmtr%252FF&md5=da5b8fc61a2f262991561c8e8a0ca567Toward safe, efficient and multifunctional 3D blood-contact adsorbents engineered by biopolymers/graphene oxide gelsHe, Ai; Lei, Bei; Cheng, Chong; Li, Shuang; Ma, Lang; Sun, Shudong; Zhao, ChangshengRSC Advances (2013), 3 (44), 22120-22129CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)In the present study, safe, efficient and multifunctional 3D GO based polymeric gels were prepd. by the promotion of different biopolymer agents. The obtained freeze-dried 3D gels have a well-defined and interconnected 3D porous network, which allows the adsorbate mols. to diffuse easily into the adsorbent. AFM images confirmed that the biopolymers had been successfully adsorbed onto the GO nanosheets through noncovalent interactions with apparently increased thicknesses. In this proposed biol. 3D noncovalent assembly, the use of biopolymers, such as proteins, DNA, and chitosan, plays an essential role in the advancement of biol. compatible adsorbents and the realization of novel, multifunctional and heterogeneous integration of materials. Meanwhile, the blood compatibility of the GO/biopolymer gels was investigated by using human red blood cells (RBCs), which indicated that the as-prepd. GO/biopolymer gels exhibited ultralow hemolysis ratio (lower than 1%) and better RBCs compatibility than the pristine GO sponge, since the adsorbed biopolymers could effectively mediate the surfactant-like property of the GO sheet. Furthermore, the 3D GO/biopolymer gels revealed ultra-high adsorption capacities against toxic cationic mols. and heavy metal ions, and presented great potential in blood purifn. fields. Moreover, the obtained gels also presented multifunctional ability, e.g. drug mol. delivery, and had high drug loading capacity and controllable releasing speed. The excellent blood compatibility and high toxic mols. loading capacity of the GO/biopolymer gels might confer it great potentials for various blood-contact applications.
- 43Wang, Y. X. J.; Hussain, S. M.; Krestin, G. P. Superparamagnetic Iron Oxide Contrast Agents: Physicochemical Characteristics and Applications in MR Imaging Eur. J. Radiol. 2001, 11, 2319– 2331
- 44Zhao, W.; Glavas, L.; Odelius, K.; Edlund, U.; Albertsson, A.-C. Facile and Green Approach towards Electrically Conductive Hemicellulose Hydrogels with Tunable Conductivity and Swelling Behavior Chem. Mater. 2014, 26, 4265– 4273
- 45Cao, X.; Prozorov, R.; Koltypin, Y.; Kataby, G.; Felner, I.; Gedanken, A. Synthesis of Pure Amorphous Fe2O3 J. Mater. Res. 1997, 12, 402– 406[Crossref], [CAS], Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXhtV2lsLY%253D&md5=c7d940959510d6e3f2d8682f3e4e20bbSynthesis of pure amorphous Fe2O3Cao, X.; Prozorov, R.; Koltypin, Yu.; Kataby, G.; Felner, I.; Gedanken, A.Journal of Materials Research (1997), 12 (2), 402-406CODEN: JMREEE; ISSN:0884-2914. (Materials Research Society)A method for the prepn. of pure amorphous Fe2O3 powder with particle size of 25 nm is reported. Pure amorphous Fe2O3 can be synthesized by the sonication of neat Fe(CO)5 or its soln. in decalin under an air atm. The Fe2O3 nanoparticles are converted to cryst. Fe3O4 nanoparticles when heated to 420° under vacuum or when heated to the same temp. under a nitrogen atm. The cryst. Fe3O4 nanoparticles were characterized by x-ray diffraction and Mossbauer spectroscopy. The Fe2O3 amorphous nanoparticles were examd. by transmission electron microscopy, differential scanning calorimetry, thermogravimetric anal., and quantum design SQUID magnetization measurements. Pure amorphous Fe2O3 has a very low magnetization at room temp. (<1.5 emu/g), and crystallizes at 268°.
- 46Glavas, L.; Odelius, K.; Albertsson, A.-C. Induced Redox Responsiveness and Electroactivity for Altering The Properties of Micelles without External Stimuli Soft Matter 2014, 10, 4028– 4036Google ScholarThere is no corresponding record for this reference.
- 47Guo, B.; Finne-Wistrand, A.; Albertsson, A.-C. Molecular Architecture of Electroactive and Biodegradable Copolymers Composed of Polylactide and Carboxyl-Capped Aniline Trimer Biomacromolecules 2010, 11, 855– 863
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Abstract

Scheme 1
Scheme 1. SRHMG Production (with H40AP16 as an example) via a Spray DryerFigure 1

Figure 1. Freshly prepared SRHMGs (a-1, b-1, c-1, d-1, and e-1), SEM images (a-2, b-2, c-2, d-2, and e-2) and size distribution (a-3, b-3, c-3, d-3, and e-3) of H40 (a-1, a-2, and a-3), H40AP16 (b-1, b-2, and b-3), H40PAA8 (c-1, c-2, and c-3), H40Fe16 (d-1, d-2, and d-3), and H40AP8PAA4 (e-1, e-2, and e-3).
Figure 2

Figure 2. UV–vis spectra of H40AP16 (a) and H40AP8PAA4 (b) in different pH aqueous buffer solutions. Images of H40AP16 (c) and H40AP8PAA4 (d) in different pH aqueous buffer solutions. Cyclic voltammograms of H40AP16 (e) and H40AP8PAA4 (f) in DMSO doped with three drops of 2 M HCl solution.
Figure 3

Figure 3. Equilibrium swelling ratio of the SRHMGs under repeated pH changes between 7.4 and 2.2 (a). Zeta potential of the SRHMGs (b).
Figure 4

Figure 4. Photos of SRHMGs (H40Fe16) in a magnetic field: solid powder state (left); 10 mg/mL in water with a magnet field supplied at the bottom of the vial (middle); 10 mg/mL in water with a magnet field supplied at left side of the vial (right).
Figure 5

Figure 5. Magnetic hysteresis of H40Fe16 (a), EDS spectrum of H40Fe16 (b), and EDS spectrum of H40 (c) microgels.
Figure 6

Figure 6. Young’s moduli of the SRHMGs measured using QNM: H40 (a), H40AP16 (b), H40PAA8 (c), H40Fe16 (d), and H40AP8PAA4 (e). (f) The surface roughness of these microgels.
Figure 7

Figure 7. Blood compatibility measurements for the SRHMGs: (a) whole blood clotting time, (b) hemolysis, (c) activated partial thromboplastin time, and (d) thrombin time. Values are expressed as the mean ± standard deviation for n = 3.
Scheme 2
Scheme 2. Synthesis of SRHMGs and Suggested Application Fields of These MicrogelsReferences
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- 5Voepel, J.; Edlund, U.; Albertsson, A.-C. Alkenyl-Functionalized Precursors for Renewable Hydrogels Design J. Polym. Sci., Polym. Chem. 2009, 47, 3595– 3606[Crossref], [CAS], Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXntVGiurw%253D&md5=8b15bed8f795d115a7a2699f4ee09b5aAlkenyl-functionalized precursors for renewable hydrogels designVoepel, Jens; Edlund, Ulrica; Albertsson, Ann-ChristineJournal of Polymer Science, Part A: Polymer Chemistry (2009), 47 (14), 3595-3606CODEN: JPACEC; ISSN:0887-624X. (John Wiley & Sons, Inc.)A library of crosslinking chemistries for the hydrogel synthesis based on the hemicellulose acetylated galactoglucomannan (AcGGM) has been developed, demonstrated, and evaluated. A three-step route was elaborated including (1) the carbonyldiimidazole activation of primary hydroxylated vinylic mols. such as acrylates, vinyl alcs., and vinyl ethers, (2) the covalent coupling of the alkenyl precursors to the polysaccharide backbone hydroxyls, and (3) the radical crosslinking of pendant vinyl functionalities affording a hydrophilic network. Crosslinking strategies explored include redox initiation and photo initiation, with an effort to adapt the suggested synthesis routes to benign conditions. The different functionalization strategies were shown to influence the resulting gel's properties. Varying the crosslinking media was found to be a strong tool to tune the properties of the gels. Modifications were in all cases verified by means of NMR and FTIR, and the gels were characterized with respect to swelling capacity and rheol. parameters. It was shown that by adjusting the synthesis parameters, the resulting properties of the AcGGM gels could be custom-made for a given performance. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3595-3606, 2009.
- 6Li, Z.; Shen, J.; Ma, H.; Lu, X.; Shi, M.; Li, N.; Ye, M. Preparation and Characterization of pH- and Temperature-Responsive Nanocomposite Double Network Hydrogels Mater. Sci. Eng., C 2013, 33, 1951– 1957[Crossref], [PubMed], [CAS], Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVGns78%253D&md5=6215d6629c3c459c3fc7223043ff8d67Preparation and characterization of pH- and temperature-responsive nanocomposite double network hydrogelsLi, Zhiqiang; Shen, Jianfeng; Ma, Hongwei; Lu, Xin; Shi, Min; Li, Na; Ye, MingxinMaterials Science & Engineering, C: Materials for Biological Applications (2013), 33 (4), 1951-1957CODEN: MSCEEE; ISSN:0928-4931. (Elsevier B.V.)A methodol. is described for the prepn. of pH- and temp.-responsive double network (DN) hydrogels with poly(N-isopropylacrylamide) (PNIPAM) as a tightly crosslinked 1st network, polyacrylic acid (PAA) as a loosely crosslinked 2nd network and graphene oxide (GO) as an additive. GO sheets were first prepd. via an oxidn. reaction and then dispersed in NIPAM aq. soln. via silanization. Free-radical polymn. of NIPAM was carried out at 20 °C in a water bath, and then subjected to UV light, leading to the formation of pH- and temp.-responsive PNIPAM/AA/GO DN hydrogels. The effects of GO sheets and AA contents on various phys. properties were investigated. Results show that PNIPAM/AA/GO hydrogels undergo a large volumetric change in response to temp. It also exhibits significantly fast swelling/deswelling compared with conventional PNIPAM hydrogel. Moreover, the PNIPAM/AA/GO hydrogels have a much better mech. property than the conventional PNIPAM hydrogels.
- 7Bigand, V.; Pinel, C.; Perez, D. D. S.; Rataboul, F.; Huber, P.; Petit-Conil, M. Cationisation of Galactomannan and Xylan Hemicelluloses Carbohydr. Polym. 2011, 85, 138– 148[Crossref], [CAS], Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkt1Gmu7s%253D&md5=a74bdcf9af5de10d1ae3c1526577e10dCationization of galactomannan and xylan hemicellulosesBigand, Virginie; Pinel, Catherine; Da Silva Perez, Denilson; Rataboul, Franck; Huber, Patrick; Petit-Conil, MichelCarbohydrate Polymers (2011), 85 (1), 138-148CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)In this study, the cationization of galactomannan and xylan hemicellulose types was investigated with 2,3-epoxypropyltrimethylammonium chloride (ETA) as reagent, under alk. conditions. The degree of substitution was accurately detd. by 1H NMR spectroscopy after hydrolysis in a DCl/D2O mixt. and confirmed by elemental analyses. The influence of reactional parameters on yield and DS was studied systematically and the reactivity of both polysaccharides was compared. DS values from 0.1 to 1.3 were obtained by varying reactional parameters, the most influential being the hemicellulose concn. and the epoxide amt. The corresponding mass yields varied from 40 to 80% of recovered hemicelluloses and were strongly correlated to DS values. The cationization of xylan was studied more particularly with a D-optimal exptl. design in order to identify interactions between parameters. The optimization of reactional parameters as a function of a desired DS allowed obtaining a maximal grafting rate of 48% with a DS value of 1.3 and 64% of mass yield.
- 8Ayoub, A.; Venditti, R. A.; Pawlak, J. J.; Salam, A.; Hubbe, M. A. Novel Hemicellulose-Chitosan Biosorbent for Water Desalination and Heavy Metal Removal ACS Sustainable Chem. Eng. 2013, 1, 1102– 1109[ACS Full Text
], [CAS], Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXps1yiurc%253D&md5=6f0bf4dc4884598bf74df98f16524b69Novel Hemicellulose-Chitosan Biosorbent for Water Desalination and Heavy Metal RemovalAyoub, Ali; Venditti, Richard A.; Pawlak, Joel J.; Salam, Abdus; Hubbe, Martin A.ACS Sustainable Chemistry & Engineering (2013), 1 (9), 1102-1109CODEN: ASCECG; ISSN:2168-0485. (American Chemical Society)Hemicellulose material is an abundant and relatively under-utilized polymeric material present in lignocellulosic materials. An alk. treatment was applied to pinewood (PW), switchgrass (SG), and coastal bermuda grass (CBG) in order to ext. hemicelluloses to subsequently produce a novel biosorbent. Alk. extn. at 75° recovered 23% of the biomass as a predominantly hemicellulose material with a no. av. d.p. of ∼450. These hemicelluloses were grafted with penetic acid (diethylene triamine pentaacetic acid, DTPA) and were then cross-linked to chitosan. The effects of hemicellulose-DTPA concn., reaction time, and temp. of reaction with chitosan on the resulting salt (NaCl) uptake and wt. loss in saline solns. were detd. A max. salt uptake for the materials was ∼0.30 g/g of foam biosorbent. The foam biosorbent was characterized by FTIR spectra, porosity, and dynamic mech. anal. Batch adsorption equil. results suggest that the adsorption process for salt follows a 2nd-order kinetic model. The hemicellulose-DTPA-chitosan foam biosorbent had uptakes of 2.90, 0.95, and 1.37 mg/g Pb2+, Cu2+, and Ni2+, resp., from aq. media at initial concns. 5000 PPB at pH 5. The cross-linked hemicellulose-DTPA-chitosan material has good potential for environmental engineering applications. - 9Zhao, W.; Glavas, L.; Odelius, K.; Edlund, U.; Albertsson, A.-C. A Robust Pathway to Electrically Conductive Hemicellulose Hydrogels with High and Controllable Swelling Behavior Polymer 2014, 55, 2967– 2976[Crossref], [CAS], Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXovVansrY%253D&md5=b3fea35979cec354022d155988410db7A robust pathway to electrically conductive hemicellulose hydrogels with high and controllable swelling behaviorZhao, Weifeng; Glavas, Lidija; Odelius, Karin; Edlund, Ulrica; Albertsson, Ann-ChristinePolymer (2014), 55 (13), 2967-2976CODEN: POLMAG; ISSN:0032-3861. (Elsevier Ltd.)A robust pathway to synthesize elec. conductive hemicellulose hydrogels (ECHHs) based on O-acetyl-galactoglucomannan (AcGGM) and conductive aniline tetramer (AT) is presented. These ECHHs were obtained by functionalizing carboxylated AcGGM with glycidyl methacrylate (GMA) and subsequently covalently immobilizing AT onto GMA. Hydrogel swelling ratios (SRs) were regulated by the degree of substitution (DS) of the carboxylated AcGGM, the max. varied as follows: SRDS=1.14 < SRDS=0.60 < SRDS=0.24. The SR can also be tuned from 548% to 228% by changing the AT contents from 10% (wt./wt.) to 40% (wt./wt.) while simultaneously altering conductivities from 2.93 × 10-8 to 1.12 × 10-6 S/cm. Free-standing ECHHs with tunable cond. and degree of swelling, as presented herein, have a broad potential for biomedical applications.
- 10Parasuraman, D.; Serpe, M. J. Poly(N-isopropylacrylamide) Microgels for Organic Dye Removal from Water ACS Appl. Mater. Interfaces 2011, 3, 2732– 2737
- 11Xia, Y.; Gu, Y.; Zhou, X.; Xu, H.; Zhao, X.; Yaseen, M.; Lu, J. R. Controllable Stabilization of Poly(N-isopropylacrylamide)-Based Microgel Films through Biomimetic Mineralization of Calcium Carbonate Biomacromolecules 2012, 13, 2299– 2308
- 12Jia, X.; Yeo, Y.; Clifton, R. J.; Jiao, T.; Kohane, D. S.; Kobler, J. B.; Zeitels, S. M.; Langer, R. Hyaluronic Acid-Based Microgels and Microgel Networks for Vocal Fold Regeneration Biomacromolecules 2006, 7, 3336– 3344
- 13Gao, Y.; Ahiabu, A.; Serpe, M. J. Controlled Drug Release from the Aggregation-Disaggregation Behavior of pH-Responsive Microgels ACS Appl. Mater. Interfaces 2014, 6, 13749– 13756[ACS Full Text
], [CAS], Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlGms7zP&md5=e91fd1cb2019801d6bdb893fcde01931Controlled Drug Release from the Aggregation-Disaggregation Behavior of pH-Responsive MicrogelsGao, Yongfeng; Ahiabu, Andrews; Serpe, Michael J.ACS Applied Materials & Interfaces (2014), 6 (16), 13749-13756CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)In this submission, two independent sets of microgels were synthesized that exhibit pH responsivity over different soln. pH ranges. The microgels were synthesized by copolymg. two different comonomers with poly(N-isopropylacrylamide) (pNIPAm). The microgels copolymd. with acrylic acid exhibit a neg. charge above pH 4.25, while the microgels copolymd. with N-[3-(dimethylamino)propyl]methacrylamide exhibit a pos. charge below pH 8.4; these microgels are neutral outside of these pH ranges. We show that aggregates form when the two independent sets of microgels are exposed to one another in a soln. that renders them both charged. Furthermore, in solns. of pH outside of this range, the microgels disaggregate because one of the microgels becomes neutralized. This behavior was exploited to load (aggregation) and release (disaggregation) a small-mol. model drug, methylene blue. This aggregate-based system is one example of how pNIPAm-based microgels can be used for controlled/triggered drug delivery, which can have implications for therapeutics. - 14Schmidt, S.; Zeiser, M.; Hellweg, T.; Duschl, C.; Fery, A.; Moehwald, H. Adhesion and Mechanical Properties of PNIPAM Microgel Films and Their Potential Use as Switchable Cell Culture Substrates Adv. Funct. Mater. 2010, 20, 3235– 3243[Crossref], [CAS], Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1KhtbvE&md5=42e32517bbe3246e8e473bf9376fc41fAdhesion and Mechanical Properties of PNIPAM Microgel Films and Their Potential Use as Switchable Cell Culture SubstratesSchmidt, Stephan; Zeiser, Michael; Hellweg, Thomas; Duschl, Claus; Fery, Andreas; Moehwald, HelmuthAdvanced Functional Materials (2010), 20 (19), 3235-3243CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)Thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) microgel films are shown to allow controlled detachment of adsorbed cells via temp. stimuli. Cell response occurs on the timescale of several minutes, is reversible, and allows for harvesting of cells in a mild fashion. The fact that microgels are attached non-covalently allows using them on a broad variety of (charged) surfaces and is a major advantage as compared to approaches relying on covalent attachment of active films. In the following, the microgels' physico-chem. parameters in the adsorbed state and their changes upon temp. variation are studied in order to gain a deeper understanding of the involved phenomena. By means of at. force microscopy (AFM), the water content, mech. properties, and adhesion forces of the microgel films are studied as a function of temp. The anal. shows that these properties change drastically when crossing the crit. temp. of the polymer film, which is the basis of the fast cell response upon temp. changes. Furthermore, nanoscale mech. anal. shows that the films posses a nanoscopic gradient in mech. properties.
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- 16Kesselman, L. R. B.; Shinwary, S.; Selvaganapathy, P. R.; Hoare, T. Synthesis of Monodisperse, Covalently Cross-Linked, Degradable “Smart” Microgels Using Microfluidics Small 2012, 8, 1092– 1098Google ScholarThere is no corresponding record for this reference.
- 17He, Y.; Chen, X.; Bi, S. Y.; Fu, W. G.; Shi, C. C.; Chen, L. Conferring pH-Sensitivity on Poly (Vinylidene Fluoride) Membrane by Poly (Acrylic Acid-co-Butyl Acrylate) Microgels React. Funct. Polym. 2014, 74, 58– 66[Crossref], [CAS], Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFOltL3K&md5=6a14cd862015972958b7505989bae850Conferring pH-sensitivity on poly (vinylidene fluoride) membrane by poly (acrylic acid-co-butyl acrylate) microgelsHe, Yang; Chen, Xi; Bi, Shiyin; Fu, Weigui; Shi, Congcong; Chen, LiReactive & Functional Polymers (2014), 74 (), 58-66CODEN: RFPOF6; ISSN:1381-5148. (Elsevier Ltd.)In this paper, crosslinked poly (acrylic acid-co-Bu acrylate) microgels were utilized to impart pH-sensitivity to poly (vinylidene fluoride) membranes by phase sepn. of a casting soln. of poly (vinylidene fluoride)/poly (acrylic acid-co-Bu acrylate)/DMF in aq. soln. The effect of microgels content on morphologies, surface compn., and chem. of the as-prepd. membranes was studied by varieties of spectroscopic and microscopic characterization techniques. By using the filtration of water and protein aq. soln., the performance of the membrane was evaluated. Results indicated that the as-prepd. membrane was pH-sensitive to water flux, bovine serum albumin rejection and antifouling property. Besides, the as-prepd. membrane showed an obvious improvement of water flux and proper bovine serum albumin rejection ratio, compared to the pristine PVDF membrane. Meanwhile, dynamic bovine serum albumin fouling resistance and flux recovery property were also greatly enhanced due to the improvement of surface hydrophilicity. Hopefully, the hydrophilic microgels additive would be favorable to fabricate other polymer membranes for water treatment.
- 18Dadsetan, M.; Taylor, K. E.; Yong, C.; Bajzer, Z.; Lu, L. C.; Yaszemski, M. J. Controlled Release of Doxorubicin from pH-Responsive Microgels Acta Biomater. 2013, 9, 5438– 5446Google ScholarThere is no corresponding record for this reference.
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], [CAS], Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XkvVKnu7k%253D&md5=4e799a90dd2db31d6bac66c66876afceCation-Condensed Microgel-Core Star Polymers as Polycationic Nanocapsules for Molecular Capture and Release in WaterFukae, Kaoru; Terashima, Takaya; Sawamoto, MitsuoMacromolecules (Washington, DC, United States) (2012), 45 (8), 3377-3386CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)Cation-condensed microgel-core star polymers with poly(ethylene glycol) (PEG)-based arms were designed as unimol. polycationic nanocapsules (hosts) to encapsulate and stimuli-responsively release hydrophilic and anionic dyes (guests) in water. Typically, a cation-condensed star polymer (core cations: ∼670/star) was directly synthesized in high yield (>90%) by the linking reaction of a PEG macroinitiator (1) with a quaternary ammonium cation-carrying linking agent (2) in ruthenium-catalyzed living radical polymn. Analyzed by UV-vis spectroscopy, the star polymer efficiently encapsulated various hydrophilic dyes carrying sulfonate anions (methyl orange: MO; orange G: OG; methyl blue: MB) in water (UV-vis: ∼400 OG per a single star). The efficient dye encapsulation is due to the high concn. of quaternary ammonium cations in the core. The no. of core-bound dyes increased with increasing the no. of core-bound cations. The ligation structure of dyes within the core was proposed: the immobilization of one OG mol. involves two in-core ammonium cations. Addnl., stimuli-responsive release of dyes from cation-condensed star polymers was successfully achieved via ion exchange with NaCl aq. soln. - 20Gao, Y. F.; Serpe, M. J. Light-Induced Color Changes of Microgel-Based Etalons ACS Appl. Mater. Interfaces 2014, 6, 8461– 8466
- 21Yue, M.; Hoshino, Y.; Ohshiro, Y.; Imamura, K.; Miura, Y. Temperature-Responsive Microgel Films as Reversible Carbon Dioxide Absorbents in Wet Environment Angew. Chem., Int. Ed. 2014, 53, 2654– 2657Google ScholarThere is no corresponding record for this reference.
- 22Berger, S.; Zhang, H.; Pich, A. Microgel-Based Stimuli-Responsive Capsules Adv. Funct. Mater. 2009, 19, 554– 559Google ScholarThere is no corresponding record for this reference.
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- 25Li, H.; Luo, R. M.; Lam, K. Y. Multiphysics Modeling of Electrochemomechanically Smart Microgels Responsive to Coupled pH/Electric Stimuli Macromol. Biosci. 2009, 9, 287– 297[Crossref], [PubMed], [CAS], Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjs1yhsr8%253D&md5=6072710ffaff67948503b18cd08202a5Multiphysics modeling of electrochemomechanically smart microgels responsive to coupled pH/electric stimuliLi, Hua; Luo, Rongmo; Lam, Khin YongMacromolecular Bioscience (2009), 9 (3), 287-297CODEN: MBAIBU; ISSN:1616-5187. (Wiley-VCH Verlag GmbH & Co. KGaA)A multiphysics model is developed to simulate the responsive behavior of smart pH-/elec.-sensitive hydrogels when immersed into pH buffer soln. and subjected to an externally applied elec. field, which is termed the MECpHe model. Comparison with exptl. data shows the MECpHe model to be accurate and stable. The influence of the externally applied elec. voltage is discussed with respect to the distribution of diffusive ionic species and the displacement of the hydrogel strip. The influences of initial charge d. and ionic strength on the swelling ratio and the bending deformation of the microgel strip are studied.
- 26Bian, S. S.; Zheng, J.; Yang, W. L. Dual Stimuli-Responsive Microgels Based on Photolabile Crosslinker: Temperature Sensitivity and Light-Induced Degradation J. Polym. Sci., Polym. Chem. 2014, 52, 1676– 1685[Crossref], [CAS], Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXks12mt70%253D&md5=7139a729c440560b6989bf0fbcd3b6a8Dual stimuli-responsive microgels based on photolabile crosslinker: Temperature sensitivity and light-induced degradationBian, Shanshan; Zheng, Jin; Yang, WuliJournal of Polymer Science, Part A: Polymer Chemistry (2014), 52 (12), 1676-1685CODEN: JPACEC; ISSN:0887-624X. (John Wiley & Sons, Inc.)The synthesis and characterization of a new photocleavable crosslinker is presented here. Dual stimuli-responsive P(VCL-co-NHMA) microgels were prepd. by pptn. polymn. of vinylcaprolactam (VCL) with N-hydroxymethyl acrylamide (NHMA) and the new crosslinker. The microgels had distinct temp. sensitivity as obsd. in the case of PVCL-based particles and their vol. phase transition temp. (VPTT) shifted to higher temp. with increasing NHMA content. Photolytic degrdn. expts. were investigated by irradn. with UV light, which led to microgel disintegration caused by cleavage of the photolabile crosslinking points. The degrdn. behavior of the microgels was conducted with respect to degrdn. rates by means of the relative turbidity changes. Hence, the microgels could totally degrade into short linear polymers by UV light, thus representing a great potential as new light and temp. dual responsive nanoscale materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014.
- 27Shi, S.; Wang, Q.; Wang, T.; Ren, S.; Gao, Y.; Wang, N. Thermo-, pH-, and Light-Responsive Poly(N-isopropylacrylamide-co-methacrylic acid)-Au Hybrid Microgels Prepared by the in Situ Reduction Method Based on Au-Thiol Chemistry J. Phys. Chem. B 2014, 118, 7177– 7186
- 28Yuan, Z. C.; Wang, Y.; Chen, D. J. Preparation and Characterization of Thermo-, pH-, and Magnetic-Field-Responsive Organic/Inorganic Hybrid Microgels Based on Poly(ethylene glycol) J. Mater. Sci. 2014, 49, 3287– 3296[Crossref], [CAS], Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlequ7Y%253D&md5=bb349d2239bf3dfd8d4377d56ec52326Preparation and characterization of thermo-, pH-, and magnetic-field-responsive organic/inorganic hybrid microgels based on poly(ethylene glycol)Yuan, Zhicheng; Wang, Yang; Chen, DajunJournal of Materials Science (2014), 49 (8), 3287-3296CODEN: JMTSAS; ISSN:0022-2461. (Springer)Nanocomposite microgels are a new class of intelligent materials because of their fast response time, large surface area, and so on. In this study, we demonstrate a new kind of multiple stimulus-responsive org./inorg. hybrid microgels by combining dual stimuli-responsive poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol)methacrylate-co-acrylic acid) (PMOA) microgels with magnetic attapulgite/Fe3O4 (AT-Fe3O4) nanoparticles. AT-Fe3O4 nanoparticles were introduced into the dual-responsive (temp. and pH) PMOA microgels network by in situ polymn. The responsive behaviors, microstructures, and the interaction between AT-Fe3O4 and PMOA microgels matrix of the prepd. microgels were systematically characterized using field emission SEM, particle size and Zeta potential analyzer, vibrating sample magnetometer, and Fourier transform IR spectroscopy. The results showed that the AT-Fe3O4 nanoparticles dispersed well in the microgel matrix, and the nanoparticles could be stably present in PMOA without phase sepn. because of the hydrogen bond (H-bond) interactions between AT-Fe3O4 nanoparticles and PMOA matrix. In addn., the multifunctional AT-Fe3O4/PMOA nanocomposite microgels had both temp./pH sensitivity and magnetic functionality.
- 29Polotsky, A. A.; Plamper, F. A.; Borisov, O. V. Collapse-to-Swelling Transitions in pH- and Thermoresponsive Microgels in Aqueous Dispersions: The Thermodynamic Theory Macromolecules 2013, 46, 8702– 8709[ACS Full Text
], [CAS], Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1GqurfE&md5=5212a53dd7dd0aafb4e76a255ac2f1ccCollapse-to-Swelling Transitions in pH- and Thermoresponsive Microgels in Aqueous Dispersions: The Thermodynamic TheoryPolotsky, Alexey A.; Plamper, Felix A.; Borisov, Oleg V.Macromolecules (Washington, DC, United States) (2013), 46 (21), 8702-8709CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)We present a theory of a conformational collapse-to-swelling transition that occurs in aq. dispersions of multiresponsive (pH- and thermoresponsive) microgels upon variation of ionic strength, temp., or pH. Our theory is based on osmotic balance arguments and explicitly accounts for ionization equil. inside microgel partices. The theory predicts complex patterns in the dependence of the microgel particle dimensions on the control parameters: An increase in temp. leads to worsening of the solvent quality for the gel forming LCST-polymers and to concomitant decrease in the dimensions of the gel particles. This collapse of the gel particles provoked by an increase in temp. occurs either smoothly (at high or low ionic strength), or may exhibit a jump-wise character at intermediate ionic strength. The theory further predicts that the degree of swelling of microgel particles varies nonmonotonously and exhibits a max. as a function of salt concn. at a pH close to the pK. This nonmonotonous variation of the particle dimensions occurs continuously at temps. below or slightly above LCST (good or marginal poor solvent strength conditions, resp.), whereas at higher temps. the jump-wise swelling of the gel particles is followed by either continuous or jump-wise collapse induced by progressive increase in the salt concn. A decrease/increase in pH leads to deswelling of the weak polyacid/polybase gel particles, which occurs smoothly at temps. below LCST, but may exhibit a discontinuity above LCST. These theor. predictions can be used for design of smart stimuli-responsive microgels. - 30Sollohub, K.; Cal, K. Spray Drying Technique: II. Current Applications in Pharmaceutical Technology J. Pharm. Sci. 2010, 99, 587– 597Google ScholarThere is no corresponding record for this reference.
- 31Vehring, R. Pharmaceutical Particle Engineering via Spray Drying Pharm. Res. 2008, 25, 999– 1022[Crossref], [PubMed], [CAS], Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXksFaiurs%253D&md5=f4762ce7b7fbc8ae4a984fb66e08d618Pharmaceutical Particle Engineering via Spray DryingVehring, ReinhardPharmaceutical Research (2008), 25 (5), 999-1022CODEN: PHREEB; ISSN:0724-8741. (Springer)A review. This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theor. framework for particle design calcns. It reviews exptl. research into parameters that influence particle formation. A classification based on dimensionless nos. is presented that can be used to est. how excipient properties in combination with process parameters influence the morphol. of the engineered particles. A wide range of pharmaceutical application examples-low d. particles, composite particles, microencapsulation, and glass stabilization-is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts.
- 32Esposito, E.; Roncarati, R.; Cortesi, R.; Cervellati, F.; Nastruzzi, C. Production of Eudragit Microparticles by Spray-Drying Technique: Influence of Experimental Parameters on Morphological and Dimensional Characteristics Pharm. Dev. Technol. 2000, 5, 267– 278Google ScholarThere is no corresponding record for this reference.
- 33De Smet, R.; Verschuere, S.; Allais, L.; Leclercq, G.; Dierendonck, M.; De Geest, B. G.; Van Driessche, I.; Demoor, T.; Cuvelier, C. A. Spray-Dried Polyelectrolyte Microparticles in Oral Antigen Delivery: Stability, Biocompatibility, and Cellular Uptake Biomacromolecules 2014, 15, 2301– 2309
- 34Ryberg, Y. Z.; Edlund, U.; Albertsson, A.-C. Innovative Approaches for Converting a Wood Hydrolysate to High-Quality Barrier Coatings ACS Appl. Mater. Interfaces 2013, 5, 7748– 7757Google ScholarThere is no corresponding record for this reference.
- 35Arias, V.; O, K.; Albertsson, A.-C. Nano-stereocomplexation of Polylactide (PLA) Spheres by Spray Droplet Atomization Macromol. Rapid Commun. 2014, 35, 1949– 1953Google ScholarThere is no corresponding record for this reference.
- 36Iwasaki, K. Production of a Functionally Graded Artificial Tooth Root by Unique Sequence of Processes Mater. Res. Innov. 1997, 1, 180– 187[Crossref], [CAS], Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXltFCksQ%253D%253D&md5=5e647b21731ce8decebd3d66b567daadProduction of a functionally graded artificial tooth root by unique sequence of processesIwasaki, KunihikoMaterials Research Innovations (1997), 1 (3), 180-187CODEN: MRINFV; ISSN:1432-8917. (Springer-Verlag)A unique sequence of processes is used to produce a prototype of a functionally graded artificial tooth root: (1) dry-jet spraying of the mixt. of Ti and Al2O3 ultrafine particles (UFPs) produced by radio-frequency plasma onto the surface of a cylindrical Ti rod, where the compn. of the UFPs is changed gradually in the outward radial direction from Ti to Al2O3; (2) temp.-gradient sintering of the deposited composite, where the Ti - and the Al2O3 - rich sides are heated simultaneously at about 1400 K and 1800 K, resp.; (3) plasma spray coating of hydroxyapatite (HAP) onto the outermost Al2O3 surface of the sintered composite. The final product has compressive strength of more than 200 MPa and is durable against fatigue test of 107 stress cycles at 1000 N. The adhesion strength between the Ti substrate and the Ti-Al2O3 functionally graded layer exceeds 65 MPa. No contamination with heavy metals is detected throughout the processes and biol. cell growth is confirmed to occur on the HAP surface. With these mech. and biochem. properties the composite produced here is considered to be highly suitable for an artificial tooth root. A series of processes developed here are expected to be applied to the prodn. of various kinds of fine-grained functionally graded materials with complicated forms.
- 37Schnieders, J.; Gbureck, U.; Germershaus, O.; Kratz, M.; Jones, D. B.; Kissel, T. Ex Vivo Human Trabecular Bone Model for Biocompatibility Evaluation of Calcium Phosphate Composites Modified with Spray Dried Biodegradable Microspheres Adv. Healthcare Mater. 2013, 2, 1361– 1369[Crossref], [PubMed], [CAS], Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsFOhurzO&md5=88b418802a44b716663ede45aa9984beEx Vivo Human Trabecular Bone Model for Biocompatibility Evaluation of Calcium Phosphate Composites Modified with Spray Dried Biodegradable MicrospheresSchnieders, Julia; Gbureck, Uwe; Germershaus, Oliver; Kratz, Marita; Jones, David B.; Kissel, ThomasAdvanced Healthcare Materials (2013), 2 (10), 1361-1369CODEN: AHMDBJ; ISSN:2192-2640. (Wiley-VCH Verlag GmbH & Co. KGaA)Our aim was to study the suitability of the ex-vivo human trabecular bone bioreactor ZetOS to test the biocompatibility of calcium phosphate bone cement composites modified with spray dried, drug loaded microspheres. We hypothesized, that this bone bioreactor could be a promising alternative to in vivo assessment of biocompatibility in living human bone over a defined time period. Composites consisting of tetracycline loaded poly(lactic-co-glycolic acid) microspheres and calcium phosphate bone cement, were inserted into in vitro cultured human femora head trabecular bone and incubated over 30 days at 37°C in the incubation system. Different biocompatibility parameters, such as lactate dehydrogenase activity, alk. phosphatase release and the expression of relevant cytokines, IL-1β, IL-6, and TNF-α, were measured in the incubation medium. No significant differences in alk. phosphatase, osteocalcin, and lactate dehydrogenase activity were measured compared to control samples. Tetracycline was released from the microspheres, delivered and incorporated into newly formed bone. In this study we demonstrated that ex vivo biocompatibility testing using human trabecular bone in a bioreactor is a potential alternative to animal expts. since bone metab. is still maintained in a physiol. environment ex vivo.
- 38Jacobs, A.; Dahlman, O. Characterization of The Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry Biomacromolecules 2001, 2, 894– 905[ACS Full Text
], [CAS], Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXkt1yru7k%253D&md5=dce8a603dd2a680e458452836b07f8d1Characterization of the molar masses of hemicelluloses from wood and pulps employing size exclusion chromatography and matrix-assisted laser desorption ionization time-of-flight mass spectrometryJacobs, Anna; Dahlman, OlofBiomacromolecules (2001), 2 (3), 894-905CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)The molar mass parameters for arabino-4-O-methylglucuronoxylans, arabinohexenuronoxylans, 4-O-methylglucuronoxylans, hexenuronoxylans, and galactoglucomannans extd. from wood and pulps were detd. To characterize different types of hemicellulose (I) samples, delignified wood (spruce, pine, larch, aspen, and birch) and chem. pulps (un-bleached and TCF-bleached) were extd. with DMSO or alk. aq. solns. SEC with off-line matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS) were employed to characterize the molar masses. The I exts. were sepd. by SEC into fractions, each contg. components with a narrow range of molar masses, and the av. molar mass of each fraction was subsequently detd. by MALDI-MS. The molar mass parameters for the I samples were then calcd. on the basis of the SEC distribution curves and MALDI-MS spectra. As expected, in most cases, the I samples extd. from wood (holocellulose) exhibited higher molar masses than did the corresponding I samples from chem. pulps. The molar mass parameters for I samples isolated from pulps derived from cooking samples of the same batch of softwood chips decreased in the following order: ASAM pulp > MSSAQ pulp > kraft pulp. The lowest molar masses were demonstrated by the glucuronoxylans extd. from pulps obtained by cooking with acidic sulfite. The xylan (II) samples from bleached kraft pulp were characterized by molar masses that were only slightly lower than those of the corresponding II samples from un-bleached pulp. The II samples extd. into DMSO exhibited somewhat lower molar masses than did the corresponding II samples extd. into alk. aq. solns. In all cases the range of molar masses demonstrated by the I samples investigated was shown to be rather narrow, i.e., the polydispersity index Mw/Mn was approx. 1.1-1.4. 6860-47-5 47592-59-6 188641-72-7 190194-13-9, (4ΔUA)-β-D-Xylopentaose 190194-14-0 190194-15-1, (4ΔUA)-β-D-Xylotetraose 190194-17-3 192331-90-1 192331-91-2 192331-92-3. - 39Huang, L.; Hu, J.; Lang, L.; Wang, X.; Zhang, P.; Jing, X.; Wang, X.; Chen, X.; Lelkes, P. I.; MacDiarmid, A. G.; Wei, Y. Synthesis and Characterization of Electroactive and Biodegradable ABA Block Copolymer of Polylactide and Aniline Pentamer Biomaterials 2007, 28, 1741– 1751Google ScholarThere is no corresponding record for this reference.
- 40Derjaguin, B. V.; Muller, V. M.; Toporov, Y. P. Effect of Contact Deformations on The Adhesion of Particles J. Colloid Interface Sci. 1975, 53, 314– 326[Crossref], [CAS], Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlGhtLrE&md5=b1cd96f05d5c46e2e72a3dcb947a8edcEffect of contact deformations on the adhesion of particlesDerjaguin, B. V.; Muller, V. M.; Toporov, Yu. P.Journal of Colloid and Interface Science (1975), 53 (2), 314-326CODEN: JCISA5; ISSN:0021-9797. (Academic Press, Inc.)A strict theory of reciprocal influence of the contact deformation and mol. attraction of a ball and a plane has been developed. It has been shown that despite the van der Waals' forces being capable of increasing the elastic contact area between the ball and the plane, the force that is required to overcome the mol. forces arising when the contact is broken does not increase thereby. In fact, it remains equal to the attraction force value that is detd. when considering the point contact of a nondeformed ball with a plane. In the absence of the electrostatic component, the adhesion force is equiv. to the first power of the ball radius and to the amt. of work per unit area as required for effecting the equil. tearing-off of a flat surface of the same nature.
- 41Zhou, H.; Cheng, C.; Qin, H.; Ma, L.; He, C.; Nie, S.; Zhang, X.; Fu, Q.; Zhao, C. Self-Assembled 3D Biocompatible and Bioactive Layer at the Macro-interface via Graphene-Based Supermolecules Polym. Chem. 2014, 5, 3563– 3575[Crossref], [CAS], Google Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXns1Wju70%253D&md5=254eec1c4193bd2067850a2dd92d4ab3Self-assembled 3D biocompatible and bioactive layer at the macro-interface via graphene-based supermoleculesZhou, Hongju; Cheng, Chong; Qin, Hui; Ma, Lang; He, Chao; Nie, Shengqiang; Zhang, Xiang; Fu, Qiang; Zhao, ChangshengPolymer Chemistry (2014), 5 (11), 3563-3575CODEN: PCOHC2; ISSN:1759-9962. (Royal Society of Chemistry)Research on the interface self-assembly of functional layers is fuelled by diverse biomedical needs, like drug encapsulation and release, stem cell proliferation and differentiation, cell and tissue cultures, as well as artificial organs. In this study, a novel and biocompatible 3D composite layer is fabricated on a membrane substrate by the layer-by-layer (LBL) self-assembly of graphene-based 2D supermols. The graphene-based 2D supermols. are prepd. by grafting poly(styrenesulfonate) (PSS, polyanion) and poly(acrylamide) (PAM, polycation) onto graphene oxide (GO) through free radical polymn. Then, the prepd. graphene-based supermols. are taken to construct a 3D porous thin film layer through a LBL process. Polyethersulfone (PES) membrane is chosen as the model substrate. The chem. compn., surface morphol., water contact angle, surface zeta-potential, blood compatibility and the cell compatibility are systematically investigated. The results indicate that the 2D graphene-based supermols. are successfully assembled into a 3D porous thin film layer structure on the membrane surface. The assembled layer shows increased hydrophilicity, suppressed platelet adhesion, and a limited hemolysis ratio and complement activation compared to the pristine substrate. The cell morphol. observation and cytotoxicity assays demonstrate that the 3D graphene layer shows superior performance both in endothelial and hepatocyte cells proliferation and morphol. differentiation. In addn., the excellent anticoagulant bioactivities indicate that the 2D graphene-based supermols. have heparin-mimicking biol. activity. In general, the protocol of interface thin film layer self-assembly confers the modified substrates with integrated blood compatibility, cell proliferation and biol. activity; which may forward the fabrication of multi-functional biomedical devices by the 2D graphene-based supermols.
- 42He, A.; Lei, B.; Cheng, C.; Li, S.; Ma, L.; Sun, S.; Zhao, C. Toward Safe, Efficient and Multifunctional 3D Blood-Contact Adsorbents Engineered by Biopolymers/Graphene Oxide Gels RSC Adv. 2013, 3, 22120– 22129[Crossref], [CAS], Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1Cmtr%252FF&md5=da5b8fc61a2f262991561c8e8a0ca567Toward safe, efficient and multifunctional 3D blood-contact adsorbents engineered by biopolymers/graphene oxide gelsHe, Ai; Lei, Bei; Cheng, Chong; Li, Shuang; Ma, Lang; Sun, Shudong; Zhao, ChangshengRSC Advances (2013), 3 (44), 22120-22129CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)In the present study, safe, efficient and multifunctional 3D GO based polymeric gels were prepd. by the promotion of different biopolymer agents. The obtained freeze-dried 3D gels have a well-defined and interconnected 3D porous network, which allows the adsorbate mols. to diffuse easily into the adsorbent. AFM images confirmed that the biopolymers had been successfully adsorbed onto the GO nanosheets through noncovalent interactions with apparently increased thicknesses. In this proposed biol. 3D noncovalent assembly, the use of biopolymers, such as proteins, DNA, and chitosan, plays an essential role in the advancement of biol. compatible adsorbents and the realization of novel, multifunctional and heterogeneous integration of materials. Meanwhile, the blood compatibility of the GO/biopolymer gels was investigated by using human red blood cells (RBCs), which indicated that the as-prepd. GO/biopolymer gels exhibited ultralow hemolysis ratio (lower than 1%) and better RBCs compatibility than the pristine GO sponge, since the adsorbed biopolymers could effectively mediate the surfactant-like property of the GO sheet. Furthermore, the 3D GO/biopolymer gels revealed ultra-high adsorption capacities against toxic cationic mols. and heavy metal ions, and presented great potential in blood purifn. fields. Moreover, the obtained gels also presented multifunctional ability, e.g. drug mol. delivery, and had high drug loading capacity and controllable releasing speed. The excellent blood compatibility and high toxic mols. loading capacity of the GO/biopolymer gels might confer it great potentials for various blood-contact applications.
- 43Wang, Y. X. J.; Hussain, S. M.; Krestin, G. P. Superparamagnetic Iron Oxide Contrast Agents: Physicochemical Characteristics and Applications in MR Imaging Eur. J. Radiol. 2001, 11, 2319– 2331
- 44Zhao, W.; Glavas, L.; Odelius, K.; Edlund, U.; Albertsson, A.-C. Facile and Green Approach towards Electrically Conductive Hemicellulose Hydrogels with Tunable Conductivity and Swelling Behavior Chem. Mater. 2014, 26, 4265– 4273
- 45Cao, X.; Prozorov, R.; Koltypin, Y.; Kataby, G.; Felner, I.; Gedanken, A. Synthesis of Pure Amorphous Fe2O3 J. Mater. Res. 1997, 12, 402– 406[Crossref], [CAS], Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXhtV2lsLY%253D&md5=c7d940959510d6e3f2d8682f3e4e20bbSynthesis of pure amorphous Fe2O3Cao, X.; Prozorov, R.; Koltypin, Yu.; Kataby, G.; Felner, I.; Gedanken, A.Journal of Materials Research (1997), 12 (2), 402-406CODEN: JMREEE; ISSN:0884-2914. (Materials Research Society)A method for the prepn. of pure amorphous Fe2O3 powder with particle size of 25 nm is reported. Pure amorphous Fe2O3 can be synthesized by the sonication of neat Fe(CO)5 or its soln. in decalin under an air atm. The Fe2O3 nanoparticles are converted to cryst. Fe3O4 nanoparticles when heated to 420° under vacuum or when heated to the same temp. under a nitrogen atm. The cryst. Fe3O4 nanoparticles were characterized by x-ray diffraction and Mossbauer spectroscopy. The Fe2O3 amorphous nanoparticles were examd. by transmission electron microscopy, differential scanning calorimetry, thermogravimetric anal., and quantum design SQUID magnetization measurements. Pure amorphous Fe2O3 has a very low magnetization at room temp. (<1.5 emu/g), and crystallizes at 268°.
- 46Glavas, L.; Odelius, K.; Albertsson, A.-C. Induced Redox Responsiveness and Electroactivity for Altering The Properties of Micelles without External Stimuli Soft Matter 2014, 10, 4028– 4036Google ScholarThere is no corresponding record for this reference.
- 47Guo, B.; Finne-Wistrand, A.; Albertsson, A.-C. Molecular Architecture of Electroactive and Biodegradable Copolymers Composed of Polylactide and Carboxyl-Capped Aniline Trimer Biomacromolecules 2010, 11, 855– 863
- 48Guo, B.; Finne-Wistrand, A.; Albertsson, A.-C. Enhanced Electrical Conductivity by Macromolecular Architecture: Hyperbranched Electroactive and Degradable Block Copolymers Based on Poly(epsilon-caprolactone) and Aniline Pentamer Macromolecules 2010, 43, 4472– 4480
- 49Dubey, N. C.; Tripathi, B. P.; Stamm, M.; Ionov, L. Smart Core-Shell Microgel Support for Acetyl Coenzyme a Synthetase: A Step toward Efficient Synthesis of Polyketide-Based Drugs Biomacromolecules 2014, 15, 2776– 2783
- 50Wu, L.; Zhang, J.; Watanabe, W. Physical and Chemical Stability of Drug Nanoparticles Adv. Drug Delivery Rev. 2011, 63, 456– 469[Crossref], [PubMed], [CAS], Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXntVyrtbY%253D&md5=97334c4a39f8f25de4e1e78dee33a32aPhysical and chemical stability of drug nanoparticlesWu, Libo; Zhang, Jian; Watanabe, WiwikAdvanced Drug Delivery Reviews (2011), 63 (6), 456-469CODEN: ADDREP; ISSN:0169-409X. (Elsevier B.V.)A review. As nano-sizing is becoming a more common approach for pharmaceutical product development, researchers are taking advantage of the unique inherent properties of nanoparticles for a wide variety of applications. This article reviews the phys. and chem. stability of drug nanoparticles, including their mechanisms and corresponding characterization techniques. A few common strategies to overcome stability issues are also discussed.
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- 52Yap, S. F.; Adams, M.; Seville, J.; Zhang, Z. Understanding The Mechanical Properties of Single Micro-Particles and Their Compaction Behaviour China Particuol. 2006, 4, 35– 40[Crossref], [CAS], Google Scholar52https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjtVSmt7o%253D&md5=d793746aebf5245e1be9646c0c8f4ab2Understanding the mechanical properties of single micro-particles and their compaction behaviourYap, Siaw Fung; Adams, Michael; Seville, Jonathan; Zhang, ZhibingChina Particuology (2006), 4 (1), 35-40CODEN: CPHACU; ISSN:1672-2515. (Science Press)The compaction of participate materials to form tablets is increasingly employed as a final dosage form for functional products due to its simplicity and low cost. However, the functionality of some products may be impaired due to the high compression pressures required. The general aim of the current study is to understand the relationship between the mech. properties of single feed particles (<100 μm) and their compaction behavior to produce tablets at low compression pressure with acceptable strength. The materials studied were pharmaceutical excipients, comprising three enteric polymer particles and three different powders in the form of agglomerates. The mech. properties of the individual particles or agglomerates were detd. by a micromanipulation technique. The samples were also compacted in cylindrical tableting dies. It was obsd. that there was a strong correlation between the forces required to cause the fracture of the single particles and those derived from the compaction measurements as detd. using an existing anal.
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- 59Nie, S.; Qin, H.; Cheng, C.; Zhao, W.; Sun, S.; Su, B.; Zhao, C.; Gu, Z. Blood Activation and Compatibility on Single-Molecular-Layer Biointerfaces J. Mater. Chem. B 2014, 2, 4911– 4921[Crossref], [CAS], Google Scholar59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtVGjs7vO&md5=2602d1eb3e3fd69fea014d33cb68651aBlood activation and compatibility on single-molecular-layer biointerfacesNie, Shengqiang; Qin, Hui; Cheng, Chong; Zhao, Weifeng; Sun, Shudong; Su, Baihai; Zhao, Changsheng; Gu, ZhongweiJournal of Materials Chemistry B: Materials for Biology and Medicine (2014), 2 (30), 4911-4921CODEN: JMCBDV; ISSN:2050-7518. (Royal Society of Chemistry)Research on the interactions between living systems and materials is fuelled by diverse biomedical needs, for example, drug encapsulation and stimulated release, stem cell proliferation and differentiation, cell and tissue cultures, as well as artificial organs. Specific single-mol.-layer biointerface design is one of the most important processes to reveal the interactions or biol. responses between synthetic biomaterials and living systems. However, until now, there is limited literature on comprehensively revealing biomaterials induced blood component activation and hemocompatibility based on the single-mol.-layer interface approach. In this study, the effects of different groups on blood compatibility are presented using single-mol.-layer silicon (Si) interfaces. Typical hydrophilic groups (hydroxyl, carboxyl, sulfonic, and amino groups) and hydrophobic groups (alkyl, benzene, and fluorinated chains) are introduced onto single-mol.-layer Si interfaces and confirmed by at. force microscopy, XPS, and water contact angle. The blood activation and compatibility for the prepd. biointerfaces are systematically investigated by protein adsorption, clotting time, Factor XII detection, platelet adhesion, contacting activation, and complement activation expts. The results indicate that the blood activation and hemocompatibility for the biointerfaces are complex and highly related to the chem. groups and hydrophilicity of the surfaces. Our results further indicate the vital importance of carefully designed biointerfaces for specific biomedical applications. The carboxyl group, sulfonic group, and hydroxyl group may be more suitable for the interface designs of antifouling materials. The results also reveal that the sulfonic group and fluorinated surface possess great potential for applications of blood contacting devices due to their low contacting blood activation.
Supporting Information
Supporting Information
ARTICLE SECTIONSThe images, IR spectra, and TGA curves of stimuli-responsive hemicellulose microgels, proposed mechanism for the HCl doping of the electroactive hemicellulose microgels, cyclic voltammograms of AP in DMSO doped by three drops of 2 M HCl solution, molecular structure of AP segment in the microgels at various oxidation states. This material is available free of charge via the Internet at http://pubs.acs.org.
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