Graphitic carbon nitride, g-C₃N₄, is a polymeric material consisting of C, N, and some impurity H, connected via tris-triazine-based patterns. Compared with the majority of carbon materials, it has electron-rich properties, basic surface functionalities and H-bonding motifs due to the presence of N and H atoms. It is thus regarded as a potential candidate to complement carbon in material applications. In this review, a brief introduction to g-C₃N₄ is given, the methods used for synthesizing this material with different textural structures and surface morphologies are described, and its physicochemical properties are referred. In addition, four aspects of the applications of g-C₃N₄ in catalysis are discussed: (1) as a base metal-free catalyst for NO decomposition, (2) as a reference material in differentiating oxygen activation sites for oxidation reactions over supported catalysts, (3) as a functional material to synthesize nanosized metal particles, and (4) as a metal-free catalyst for photocatalysis. The reasons for the use of g-C₃N₄ for such applications are also given, and we expect that this paper will inspire readers to search for further new applications for this material in catalysis and in other fields.

Aerodynamically focused nanoparticle (AFN) printing was demonstrated for direct patterning of the solvent-free and inorganic nanoparticles. The fast excitation-purge control technique was proposed and investigated by examining the aerodynamic focusing of nanoparticles and their time-scale, with the analytical and experimental approaches. A series of direct patterning examples were demonstrated with Barium Titanate (BaTiO₃) and Silver (Ag) nanoparticles onto the flexible and inflexible substrates using the AFN printing system. The capacitor and flexible conductive line pattern were fabricated as the application examples of the proposed technique. The results presented here should contribute to the nanoparticle manipulation, patterning, and their applications, which are intensely being studied nowadays.

We report a massive increase in the electrical conductivity of a multilayer graphene (MLG)/polystyrene composite following the addition of nonconducting silica nanoparticles. The nonconducting filler acts as a highly effective dispersion aid, preventing the sheetlike MLG from restacking or agglomerating during the solvent casting process used to fabricate the composite. The enhanced dispersion of the MLG leads to orders of magnitude enhancement in electrical conductivity compared to samples without this filler.

3,6-Bis(N,N-dianisylamino)-fluoren-9-ylidene malononitrile (FMBDAA36) was used as an electron donor material in solution-processed organic photovoltaic devices with configuration ITO/PEDOT:PSS/(1:3[w/w] FMBDAA36:PC₇₁BM)/LiF/Al to give power conversion efficiencies up to 4.1% with open circuit voltage V_OC = 0.89 V, short circuit current J_SC = 10.35 mA cm^–2, and fill factor FF = 44.8%. Conductive atomic force microscopy of the active layer showed granular separation of regions exhibiting easy versus difficult hole transport, consistent with bulk heterojunction type phase separation of FMBDAA36 and PC₇₁BM, respectively. Single-crystal X-ray diffraction analysis showed pure FMBDAA36 to form columnar π-stacks with a 3.3 Å intermolecular spacing.

Herein, we report the use of upconversion agents to modify graphite carbon nitride (g-C₃N₄) by direct thermal condensation of a mixture of ErCl₃·6H₂O and the supramolecular precursor cyanuric acid-melamine. We show the enhancement of g-C₃N₄ photoactivity after Er³⁺ doping by monitoring the photodegradation of Rhodamine B dye under visible light. The contribution of the upconversion agent is demonstrated by measurements using only a red laser. The Er³⁺ doping alters both the electronic and the chemical properties of g-C₃N₄. The Er³⁺ doping reduces emission intensity and lifetime, indicating the formation of new, nonradiative deactivation pathways, probably involving charge-transfer processes.

A superparamagnetic nanoferrite (SPNF) with high magnetic moment, AC magnetically induced heating (AC-heating) capacity, and good biocompatibility is the most vital part of magnetic fluid hyperthermia for utilizing it in the clinics. Herein, we precisely tune magnetic properties and AC-heating characteristics of Mg_xMn_1–xFe₂O₄ SPNF via chemically controlling the cations’ concentration and distribution to develop a tailored Mg_xMn_1–xFe₂O₄ SPNF as a potential magnetic fluid hyperthermia agent. The magnetic and AC-heating characteristics of the tailored Mg_xMn_1–xFe₂O₄ SPNF are strongly dependent on the Mg/Mn cations’ concentration and distribution, and Mg_0.285Mn_0.715Fe₂O₄ SPNF exhibits the highest saturation magnetization and AC-heating capacity as well as high biocompatibility.

Engineering surface morphology as in honeycomb-structured planar films is of great importance for providing new potential application and improved performance in biomedical fields. We demonstrate potential new applications for the uniform biocompatible golf-ball-shaped microparticles that resembles 3D feature of honeycomb-structured film. Dimple size controllable golf-ball-shaped microparticles were fabricated by microfluidic device. Surface dimples not only can act as picoliter beaker but also enhance cell adhesion without any chemical modification of the surface.

The exposed facets of a crystal are known to be one of the key factors to its physical, chemical and electronic properties. Herein, we demonstrate the role of amines on the controlled synthesis of TiO₂ nanocrystals (NCs) with diverse shapes and different exposed facets. The chemical, physical and electronic properties of the as-synthesized TiO₂ NCs were evaluated and their photoredox activity was tested. It was found that the intrinsic photoredox activity of TiO₂ NCs can be enhanced by controlling the chemical environment of the surface, i.e.; through morphology evolution. In particular, the rod shape TiO₂ NCs with ∼25% of {101} and ∼75% of {100}/{010} exposed facets show 3.7 and 3.1 times higher photocatalytic activity than that of commercial Degussa P25 TiO₂ toward the degradation of methyl orange and methylene blue, respectively. The higher activity of the rod shape TiO₂ NCs is ascribed to the facetsphilic nature of the photogenerated carriers within the NCs. The photocatalytic activity of TiO₂ NCs are found to be in the order of {101}+{100}/{010} (nanorods) > {101}+{001}+{100}/{010} (nanocuboids and nanocapsules) > {101} (nanoellipsoids) > {001} (nanosheets) providing the direct evidence of exposed facets-depended photocatalytic activity.

The synthesis of nanocomposite with controlled surface morphology plays a key role for pollutant removal from aqueous environments. The influence of the molecular size of the polyelectrolyte in synthesizing silica–iron oxide core–shell nanocomposite with open shell structure was investigated by using dynamic light scattering, atomic force microscopy, and quartz crystal microbalance with dissipation (QCM-D). Here, poly(diallydimethylammonium chloride) (PDDA) was used to promote the attachment of iron oxide nanoparticles (IONPs) onto the silica surface to assemble a nanocomposite with magnetic and catalytic bifunctionality. High molecular weight PDDA tended to adsorb on silica colloid, forming a more extended conformation layer than low molecular weight PDDA. Subsequent attachment of IONPs onto this extended PDDA layer was more randomly distributed, forming isolated islands with open space between them. By taking amoxicillin, an antibiotic commonly found in pharmaceutical waste, as the model system, better removal was observed for silica–iron oxide nanocomposite with a more extended open shell structure.

The removal of old glue from paper artworks is of paramount importance for the preservation of its integrity during the restoration process. Wet cleaning is one of the traditional methods, although it may cause damages on artworks. In this work, an advantageous alternative method, based on the use of a rigid hydrogel, for a simple and localized removal of starch paste from paper supports is presented. The use of an appropriate hydrogel allows to overcome many of the problems faced by restorers minimizing damages, through a controlled release of water to the artwork, and a simple and not invasive application and removal. At the same time, the specific and targeted enzyme activity leads to a significant reduction in the application time of the cleaning procedure. In this context, experiments were carried out applying Gellan hydrogel carrying α-amylase enzyme on several paper samples soiled with starch paste. To assess the cleaning efficacy of the proposed hydrogel, we have used a multidisciplinary approach, by means of spectroscopic techniques, scanning electron microscopy, chromatographic analysis, and pH investigations.

On the basis of cell cultures involving bacterial strains (Escherichia coli 5α and Bacillus subtilis 168) and a mammalian cell line (NIH 3T3), the potent antibacterial activity and distinct selectivity from designed amphiphilic peptides G(IIKK)_nI-NH₂ (n = 2–4) have been demonstrated. This work extends these studies to multidrug resistant pathogens (ESBL-producing E. coli) and primary human cells (HDFa), followed by the in vivo mouse model investigation of ESBL-producing bacterial infection. G(IIKK)₃I-NH₂ exhibits high antibacterial activity against the pathogenic strain both in vitro and in vivo while displaying low toxicity toward the primary cells and the mice. Peptide molecules can kill bacteria by selectively interacting with bacterial membranes, causing structural disruptions. Furthermore, multidrug resistant ESBL-producing bacteria do not develop resistance after multiple treatments with G(IIKK)₃I-NH₂. The high cellular selectivity, low toxicity toward mammalian hosts and noninducing bacterial resistance indicate great potential for developing the peptides as anti-infection agents.

CuO_x nanowires were synthesized by a low-cost and large-scale electrochemical process with AAO membranes at room temperature and its resistive switching has been demonstrated. The switching characteristic exhibits forming-free and low electric-field switching operation due to coexistence of significant amount of defects and Cu nanocrystals in the partially oxidized nanowires. The detailed resistive switching characteristics of CuO_x nanowire systems have been investigated and possible switching mechanisms are systematically proposed based on the microstructural and chemical analysis via transmission electron microscopy.

Nitrogen-doped/undoped thermally reduced graphene oxide (N-rGO) decorated with CoMn₂O₄ (CMO) nanoparticles were synthesized using a simple one-step hydrothermal method. The activity and stability of this hybrid catalyst were evaluated by preparing air electrodes with both primary and rechargeable zinc–air batteries that consume ambient air. Further, we investigated the relationship between the physical properties and the electrochemical results for hybrid electrodes at various cycles using X-ray diffraction, scanning electron microscopy, galvanodynamic charge–discharging and electrochemical impedance spectroscopy. The structural, morphological and electrocatalytic performances confirm that CMO/N-rGO is a promising material for safe, reliable, and long-lasting air cathodes for both primary and rechargeable zinc–air batteries that consume air under ambient condition.

We have prepared nanoporous SnO₂ hollow microspheres (HMS) by employing the resorcinol-formaldehyde (RF) gel method. Further, we have investigated the electrochemical property of SnO₂–HMS as negative electrode material in rechargeable Li-ion batteries by employing three different binders—polyvinylidene difluoride (PVDF), Na salt of carboxy methyl cellulose (Na-CMC), and Na-alginate. At 1C rate, SnO₂ electrode with Na-alginate binder exhibits discharge capacity of 800 mA h g^–1, higher than when Na-CMC (605 mA h g^–1) and PVDF (571 mA h g^–1) are used as binders. After 50 cycles, observed discharge capacities were 725 mA h g^–1, 495 mA h g^–1, and 47 mA h g^–1, respectively, for electrodes with Na-alginate, Na-CMC, and PVDF binders that amounts to a capacity retention of 92%, 82%, and 8% . Electrochemical impedance spectroscopy (EIS) results confirm that the SnO₂ electrode with Na-alginate as binder had much lower charge transfer resistance than the electrode with Na-CMC and PVDF binders. The superior electrochemical property of the SnO₂ electrode containing Na-alginate can be attributed to the cumulative effects arising from integration of nanoarchitecture with a suitable binder; the hierarchical porous structure would accommodate large volume changes during the Li interaclation–deintercalation process, and the Na-alginate binder provides a stronger adhesion betweeen electrode film and current collector.

Significant differences in catalyst performance and durability are often observed between the use of a liquid electrolyte (e.g., sulfuric acid), and a solid polymer electrolyte (e.g., Nafion). To understand this phenomenon, we studied the electrochemical behavior of a commercially available carbon supported platinum catalyst in four different electrode structures: catalyst powder (CP), catalyst ionomer electrode (CIE), half membrane electrode assembly (HMEA), and full membrane electrode assembly (FMEA) in both ex situ and in situ experiments under a simulated start/stop cycle. We found that the catalyst performance and stability are very much influenced by the presence of the Nafion ionomers. The proton conducting phase provided by the ionomer and the self-assembled electrode structure render the catalysts a higher utilization and better stability. This is probably due to an enhanced dispersion, an improved proton–catalyst interface, the restriction of catalyst particle aggregation, and the improved stability of the ionomer phase especially after the lamination. Therefore, an innovative electrode HMEA design for ex-situ catalyst characterization is proposed. The electrode structure is identical to the one used in a real fuel cell, where the protons transport takes place solely through solid state proton conducting phase.

Ionic composites based on cross-linked chitosan (CS) as matrix and poly(amidoxime) grafted on potato starch (AOX) as entrapped chelating resin were prepared as beads, for the first time in this work, by two strategies: (1) thorough mixing of previously prepared AOX in the CS solution followed by the bead formation and (2) thorough mixing of the potato starch-g-poly(acrylonitrile) (PS-g-PAN) copolymer in the initial CS solution, followed by bead formation, the amidoximation of the nitrile groups taking place inside the beads. Ionotropic gelation in tripolyphosphate was used to obtain the composite beads, and in situ covalent cross-linking by epichlorohydrin was carried out to stabilize the beads in the acidic pH range. Fourier transform infrared spectroscopy and the swelling ratio values in the acidic pH range confirmed the influence of the synthesis strategy on the structure of the CS/AOX composites. Scanning electron microscopy was employed to reveal the morphology of the novel composites, both before and after their loading with Cu²⁺. The binding capacity of Cu²⁺ ions as a function of sorbent composition, synthesis strategy, pH, sorbent dose, contact time, initial concentration of Cu²⁺, and temperature was examined in batch mode. The main difference between the composites prepared with the two strategies consisted of the higher sorption capacity and the much faster settlement of the equilibrium sorption for the composite prepared by the in situ amidoximation of PS-g-PAN. The Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, and Sips isotherms were applied to fit the sorption equilibrium data. The maximum equilibrium sorption capacity, q_m, evaluated by the Langmuir model at 25 °C was 133.15 mg Cu²⁺/g for the CS/AOX composite beads prepared with the first strategy and 238.14 mg Cu²⁺/g for the CS/AOX composite beads prepared with the second strategy, at the same AOX content. The pseudo-second order kinetic model well fitted the sorption kinetics data, supporting chemisorption as the mechanism of interaction between the chelating composites and the Cu²⁺ ions. The CS/AOX composite sorbents could be reused up to five sorption/desorption cycles with no significant decrease in Cu²⁺ sorption capacity.

Titanium dioxide (TiO₂)-layered fluorine doped tin oxide (FTO) powder was synthesized and applied as the photoanode in dye-sensitized solar cells (DSSCs). FTO powders are connected to form a direct electron pathway for the efficient extract of injected electrons, while the TiO₂ layer serves as an energy barrier prohibiting the charge combination with oxidized dye or I₃^–. The electrochemical impedance spectroscopy (EIS) analyses suggest that electrons have a longer combination lifetime (τ_e = 233 ms) than that of the electron in the DSSCs using traditional P25 photoanodes (τ_e = 28 ms). The DSSCs using 5 μm thick TiO₂@FTO as photoanodes eventually give a respectable and long-term stable photovoltaic performance with a current density of 23.8 mA/cm², an open circuit voltage of 0.69 V, and power conversion efficiency of 7.4%. The results are received on a low dye loading level (0.25 × 10^–7 mol/cm²), which is ¹/₁₀ of that for traditional photoanode (2.79 × 10^–7 mol/cm²).

This paper reports improvements in the electrical and optical properties of blue-emission gallium nitride (GaN)-based thin-film light-emitting diodes (TFLEDs) after laser-based Si doping (LBSD) of a nitrogen-face n-GaN (denoted as hereafter n-GaN) layer. Experimental results show that the light-output powers of the flat- and rough-surface TFLEDs after LBSD are 52.1 and 11.35% higher than those before LBSD, respectively, at a current of 350 mA, while the corresponding operating voltages are decreased by 0.22 and 0.28 V for the flat- and rough-surface TFLEDs after LBSD, respectively. The reduced operating voltage after LBSD of the top n-GaN layer may result from the remarkably decreased specific contact resistance at the metal/n-GaN interface and the low series resistance of the TFLED device. The LBSD of n-GaN increases the number of nitrogen vacancies, and Si substitutes for Ga (Si_Ga) at the metal/n-GaN interface to produce highly Si-doped regions in n-GaN, leading to a decrease in the Schottky barrier height and width. As a result, the specific contact resistances are significantly decreased to 1.56 × 10^–5 and 2.86 × 10^–5 Ω cm² for the flat- and rough-surface samples after LBSD, respectively. On the other hand, the increased light-output power after LBSD can be explained by the uniform current spreading, efficient current injection, and enhanced light scattering resulting from the low contact resistivity, low lateral current resistance, and additional textured surface, respectively. Furthermore, LBSD did not degrade the electrical properties of the TFLEDs owing to low reverse leakage currents. The results indicate that our approach could potentially enable high-efficiency and high-power capabilities for optoelectronic devices.

Bioceramics are used to treat bone defects but in general do not induce formation of new bone, which is essential for regeneration process. Many aspects related to bioceramics synthesis, properties and biological response that are still unknown and, there is a great need for further development. In the most recent research efforts were aimed on creation of materials from biological precursors of apatite formation in humans. One possible precursor is octacalcium phosphate (OCP), which is believed to not only exhibit osteoconductivity but possess osteoinductive quality, the ability to induce bone formation. Here we propose a relatively simple route for OCP ceramics preparation with a specifically designed microstructure. Comprehensive study for OCP ceramics including biodegradation, osteogenic properties in ortopic and heterotopic models and limited clinical trials were performed that demonstrated enhanced biological behavior. Our results provide a possible new concept for the clinical applications of OCP ceramics.

Surface functionalization of pretreated carbon nanotubes (CNT) using aromatic, aliphatic, and aliphatic ether diamines was performed. The pretreatment of the CNT consisted of either acid- or photo-oxidation. The acid treated CNT had a higher initial oxygen content compared to the photo-oxidized CNT and this resulted in a higher density of functionalization. X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) were used to verify the presence of the oxygenated and amine moieties on the CNT surfaces. Epoxy/0.1 wt % CNT nanocomposites were prepared using the functionalized CNT and the bulk properties of the nanocomposites were examined. Macroscale correlations between the interfacial modification and bulk dynamic mechanical and thermal properties were observed. The amine modified epoxy/CNT nanocomposites exhibited up to a 1.9-fold improvement in storage modulus (G′) below the glass transition (T_g) and up to an almost 4-fold increase above the T_g. They also exhibited a 3–10 °C increase in the glass transition temperature. The aromatic diamine surface modified epoxy/CNT nanocomposites resulted in the largest increase in shear moduli below and above the T_g and the largest increase in the T_g. Surface examination of the nanocomposites with scanning electron microscopy (SEM) revealed indications of a greater adhesion of the epoxy resin matrix to the CNT, most likely due to the covalent bonding.

A facile bottom-up approach for the synthesis of inorganic/organic bioconjugated nanoprobes based on iron oxide nanocubes as the core with a nanometric silica shell is demonstrated. Surface coating and functionalization protocols developed in this work offered good control over the shell thickness (8–40 nm) and enabled biovectorization of SiO₂@Fe₃O₄ core–shell structures by covalent attachment of folic acid (FA) as a targeting unit for cellular uptake. The successful immobilization of folic acid was investigated both quantitatively (TGA, EA, XPS) and qualitatively (AT-IR, UV–vis, ζ-potential). Additionally, the magnetic behavior of the nanocomposites was monitored after each functionalization step. Cell viability studies confirmed low cytotoxicity of FA@SiO₂@Fe₃O₄ conjugates, which makes them promising nanoprobes for targeted internalization by cells and their imaging.

Organic/inorganic nanohybrids, which integrate advantages of the biocompatibility of organic polymers and diversified functionalities of inorganic nanoparticles, have been extensively investigated in recent years. Herein, we report the construction of arginine-glycine-aspartic acid-cysteine (RGDC) tetrapeptide functionalized and 10-hydroxycamptothecin (HCPT)-encapsulated magnetic nanohybrids (RFHEMNs) for integrin α_Vβ₃-targeted drug delivery. The obtained RFHEMNs were near-spherical in shape with a homogeneous size about 50 nm, and exhibited a superparamagnetic behavior. In vitro drug release study showed a sustained and pH-dependent release profile. Cell viability tests revealed that RFHEMNs displayed a significant enhancement of cytotoxicity against α_Vβ₃-overexpressing A549 cells, as compared to free HCPT and nontargeting micelles. Flow cytometry analysis indicated that this cytotoxic effect was associated with dose-dependent S phase arrest. Finally, RFHEMNs exerted encouraging anti-cell-migration activity as determined by an in vitro wound-healing assay and a transwell assay. Overall, we envision that this tumor-targeting nanoscale drug delivery system may be of great application potential in chemotherapy of primary tumor and their metastases.

In this research, hierarchical porous TiO₂ ceramics were successfully synthesized through a camphene-based freeze-drying route. The well-dispersed TiO₂ slurries were first frozen and dried at room temperature, followed by high-temperature sintering. The ceramics were analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Results indicated that the obtained TiO₂ ceramics could inhibit undesirable anatase-to-rutile phase transformation and grain growth even at temperatures as high as 800 °C. In this experiment, optimal compressive strength and porosity of the TiO₂ ceramics were produced with the initial TiO₂ slurry content of ∼15 wt %. The resultant TiO₂ ceramics performed excellently in the photodegradation of atrazine and thiobencarb, and the total organic carbon removal efficiency was up to 95.7% and 96.7%, respectively. More importantly, the TiO₂ ceramics were easily recyclable. No obvious changes of the photocatalytic performance were observed after six cycles. Furthermore, the ceramics also effectively degraded other pesticides such as dimethoate, lindane, dipterex, malathion, and bentazone. These hierarchical porous TiO₂ ceramics have potential applications in environmental cleanup.

We report that conductive films made from hexadecylated graphene nanoribbons (HD-GNRs) can have high transparency to radiofrequency (RF) waves even at very high incident power density. Nanoscale-thick HD-GNR films with an area of several square centimeters were found to transmit up to 390 W (2 × 10⁵ W/m²) of RF power with negligible loss, at an RF transmittance of ∼99%. The HD-GNR films conformed to electromagnetic skin depth theory, which effectively accounts for the RF transmission. The HD-GNR films also exhibited sufficient optical transparency for tinted glass applications, with efficient voltage-induced deicing of surfaces. The dispersion of the HD-GNRs afforded by their edge functionalization enables spray-, spin-, or blade-coating on almost any substrate, thus facilitating flexible, conformal, and large-scale film production. In addition to use in antennas and radomes where RF transparency is crucial, these capabilities bode well for the use of the HD-GNR films in automotive and general glass applications where both optical and RF transparencies are desired.

A simple one-step, low-temperature, urea-modulated method is developed for the synthesis of layered protonated titanate nanosheets (LPTNs). Urea serves as an indirect ammonium ion source, and the controlled supply of the ammonium ion slows the crystalline formation process and enables the production of the LPTNs from amorphous intermediate through aging-induced restructuring. The resulting LPTNs exhibit excellent adsorption capacities for methylene blue and Pb²⁺ because of their high specific surface areas and excellent ion-exchange capability. Intercalation of Pb²⁺ into the interlayer space of the LPTNs is evidenced by the relevant X-ray diffraction patterns on perturbation of the layered structure. The LPTNs prove to be a promising adsorbent in wastewater treatment for adsorption removal of metal ions or cationic organic dyes.

The significance of developing implantable, biocompatible, miniature power sources operated in a low current range has become manifest in recent years to meet the demands of the fast-growing market for biomedical microdevices. In this work, we focus on developing high-performance cathode material for biocompatible zinc/polymer batteries utilizing biofluids as electrolyte. Conductive polymers and graphene are generally considered to be biocompatible and suitable for bioengineering applications. To harness the high electrical conductivity of graphene and the redox capability of polypyrrole (PPy), a polypyrrole fiber/graphene composite has been synthesized via a simple one-step route. This composite is highly conductive (141 S cm^–1) and has a large specific surface area (561 m² g^–1). It performs more effectively as the cathode material than pure polypyrrole fibers. The battery constructed with PPy fiber/reduced graphene oxide cathode and Zn anode delivered an energy density of 264 mWh g^–1 in 0.1 M phosphate-buffer saline.

The development of pH-sensitive drug delivery nanosystems that present a low drug release at the physiological pH and are able to increase the extent of the release at a lower pH value (like those existent in the interstitial space of solid tumors (pH 6.5) and in the intracellular endolysosomal compartments (pH 5.0)) is very important for an efficient and safe cancer therapy. Laponite (LP) is a synthetic silicate nanoparticle with a nanodisk structure (25 nm in diameter and 0.92 nm in thickness) and negative-charged surface, which can be used for the encapsulation of doxorubicin (DOX, a cationic drug) through electrostatic interactions and exhibit good pH sensitivity in drug delivery. However, the colloidal instability of LP still limits its potential clinical applications. In this study, we demonstrate an elegant strategy to develop stable Laponite-based nanohybrids through the functionalization of its surface with an amphiphile PEG–PLA copolymer by a self-assembly process. The hydrophobic block of PEG–PLA acts as an anchor that binds to the surface of drug-loaded LP nanodisks, maintaining the core structure, whereas the hydrophilic PEG part serves as a protective stealth shell that improves the whole stability of the nanohybrids under physiological conditions. The resulting nanocarriers can effectively load the DOX drug (the encapsulation efficiency is 85%), and display a pH-enhanced drug release behavior in a sustained way. In vitro biological evaluation indicated that the DOX-loaded nanocarriers can be effectively internalized by CAL-72 cells (an osteosarcoma cell line), and exhibit a remarkable higher anticancer cytotoxicity than free DOX. The merits of Laponite/PEG–PLA nanohybrids, such as good cytocompatibility, excellent physiological stability, sustained pH-responsive release properties, and improved anticancer activity, make them a promising platform for the delivery of other therapeutic agents beyond DOX.

Repairing osteochondral defects (OCD) remains a formidable challenge due to the high complexity of native osteochondral tissue and the limited self-repair capability of cartilage. Osteochondral tissue engineering is a promising strategy for the treatment of OCD. In this study, we fabricated a novel integrated trilayered scaffold using silk fibroin and hydroxyapatite by combining paraffin-sphere leaching with a modified temperature gradient-guided thermal-induced phase separation (TIPS) technique. This biomimetic scaffold is characterized by three layers: a chondral layer with a longitudinally oriented microtubular structure, a bony layer with a 3D porous structure and an intermediate layer with a dense structure. Live/dead and CCK-8 tests indicated that this scaffold possesses good biocompatibility for supporting the growth, proliferation, and infiltration of adipose-derived stem cells (ADSCs). Histological and immunohistochemical stainings and real-time polymerase chain reaction (RT-PCR) confirmed that the ADSCs could be induced to differentiate toward chondrocytes or osteoblasts in vitro at chondral and bony layers in the presence of chondrogenic- or osteogenic-induced culture medium, respectively. Moreover, the intermediate layer could play an isolating role for preventing the cells within the chondral and bony layers from mixing with each other. In conclusion, the trilayered and integrated osteochondral scaffolds can effectively support cartilage and bone tissue generation in vitro and are potentially applicable for OC tissue engineering in vivo.

Alloy composition homogeneity plays an important role in the device performance of III–V heterostructures. In this work, we study the spatial composition uniformity of n-In_0.12Ga_0.88As/i-In_0.2Ga_0.8As/p-GaAs core–shell nanopillars monolithically grown on silicon. Cross sections extracted along the axial and radial directions are examined with transmission electron microscopy and energy-dispersive X-ray spectroscopy. Interestingly, indium-deficient segments with width ∼5 nm are observed to develop along the radial ⟨112̅0⟩ directions in the InGaAs layers. We attribute this spontaneous ordering to capillarity effect and difference in group-III adatom diffusion lengths. The slight fluctuation in indium content (∼4%), however, does not induce any noticeable misfit defects in the pure wurtzite-phased crystal. In contrast, the heterostructure exhibits excellent alloy composition uniformity along the axial [0001] direction. Furthermore, abrupt transitions of gallium and indium are seen at the heterointerfaces. These remarkable properties give rise to extraordinary optical performances. Lasing is achieved in the core–shell nanopillars upon optical pump despite the observed alloy composition fluctuation in the radial directions. The results here reveal the potential of the InGaAs-based core–shell heterostructures as efficient optoelectronic devices and high-speed heterojunction transistors directly integrated on silicon.

Doped TiO₂ with metal, nonmetal, and rare earth elements has shown a great potential in energy and environmental applications, but it is difficult to dope well-defined TiO₂ single crystals (SCs) with {001} exposed facet due to their high crystallinity. In this work, we developed a green and general approach to prepare the {001}-exposed TiO₂ SCs doped with various elements, on the basis of recycling the wasted ethylene glycol electrolyte from the anodic oxidation for TiO₂ nanotube preparation. All six representative elements (i.e., metal, nonmetal, and rare earth types) could be successfully doped into the TiO₂ SCs without breaking their single-crystalline structure and exposed high-energy facet. The electronic properties of the doped TiO₂ SCs were significantly improved. All the doped TiO₂ SCs exhibited a superior photoactivity under visible-light irradiation for degrading rhodamine B, a typical organic pollutant. The prepared doped TiO₂ SCs have a promising potential in environmental and energy applications.

Constructing electrocatalysts with enhanced activity and stability is necessary due to the increasing demands of the fuel cell industry. This work demonstrates a facile approach to synthesize well-defined three-dimensional (3D) PtM (M = Fe, Co, Cu, Ni) bimetallic alloy nanosponges (BANs) in the presence of Al. Significantly, with the aid of Al, the as-prepared BANs exhibit greatly enhanced electrochemistry catalytic activity in an oxygen reduction reaction (ORR), and PtFe BANs appear the best ORR property among the four BANs and commercial Pt/C catalysts. This work may provide a universal approach for convenient and large-scale fabrication of porous bimetallic nanocatalysts, thus providing promising potential application as an efficient cathodic component in fuel cells for industrial production.

Recently, one-dimensional photonic crystals (1DPCs) have attracted considerable interest because they exhibit a material-specific response profile to external stimuli. In our previous work, TiO₂/GO 1DPCs, the stopbands of which can be made to span the whole visible range, were fabricated by spin-coating technique. The prepared 1DPCs have a double response to both dimethyl sulfoxide and alkali solution. However, the response is slow, insensitive, and irreversible. To improve the responsiveness of the 1DPCs, poly(ethylene glycol) (PEG)-cross-linked poly((methyl vinyl ether)-co-maleic acid) (PMVE-co-MA) hydrogels were embedded in those crystals. The results demonstrated that modified 1DPCs with different stopbands could be obtained by controlling the speed of the spin-coating technique. The prepared 1DPCs have better responsiveness to external solution pH.

We describe a facile route to fabricate mesoporous metal oxide (TiO₂, CeO₂ and ZrO_1.95) nanotubes for efficient water retention and migration in a Nafion membrane operated in polymer electrolyte fuel cell under low relative humidity (RH). Porous TiO₂ nanotubes (TNT), CeO₂ nanotubes (CeNT), and ZrO_1.95 (ZrNT) were synthesized by calcining electrospun polyacrylonitrile nanofibers embedded with metal precursors. The nanofibers were prepared using a conventional single spinneret electrospinning technique under an ambient atmosphere. Their porous tubular morphology was observed by SEM and TEM analyses. HR-TEM results revealed a porous metal oxide wall composed of small particles joined together. The mesoporous structure of the samples was analyzed using BET. The tubular morphology and outstanding water absorption ability of the TNT, CeNT, and ZrNT fillers resulted in the effective enhancement of proton conductivity of Nafion composite membranes under both fully humid and dry conditions. Compared to a commercial membrane (Nafion, NRE-212) operated under 100% RH at 80 °C, the Nafion–TNT composite membrane delivered approximately 1.29 times higher current density at 0.6 V. Compared to the Nafion-TiO₂ nanoparticles membrane, the Nafion–TNT membrane also generated higher current density at 0.6 V. Additionally, compared to a NRE-212 membrane operated under 50% RH at 80 °C, the Nafion–TNT composite membrane exhibited 3.48 times higher current density at 0.6 V. Under dry conditions (18% RH at 80 °C), the Nafion–TNT, Nafion-CeNT, and Nafion-ZrNT composite membranes exhibited 3.4, 2.4, and 2.9 times higher maximum power density, respectively, than the NRE-212 membrane. The remarkably high performance of the Nafion composite membrane was mainly attributed to the reduction of ohmic resistance by the mesoporous hygroscopic metal oxide nanotubes, which can retain water and effectively enhance water diffusion through the membrane.

Carbon nitride (C₃N₄) is a layered, stable, and polymeric metal-free material that has been discovered as a visible-light-response photocatalyst. Owing to C₃N₄ having a higher conduction band position, most previous studies have been focused on its reduction capability for solar fuel production, such as hydrogen generation from water splitting or hydrocarbon production from CO₂. However, photooxidation ability of g-C₃N₄ is weak and has been less explored, especially for decomposition of chemically stable phenolics. Carbon spheres prepared by a hydrothermal carbonization of glucose have been widely applied as a support material or template due to their interesting physicochemical properties and the functional groups on the reactive surface. This study demonstrated that growth of carbon nanospheres onto g-C₃N₄ (CN-CS) can significantly increase the photooxidation ability (to about 4.79 times higher than that of pristine g-C₃N₄) in phenol degradation under artificial sunlight irradiations. The crystal structure, optical property, morphology, surface groups, recombination rate of electron/hole pairs, and thermal stability of CN-CS were investigated by a variety of characterization techniques. This study contributes to the further promising applications of carbon nitride in metal-free catalysis.

Hexagonal boron nitride (h-BN) atomic layers are synthesized on polycrystalline copper foils via a novel chemical vapor deposition (CVD) process that maintains a vapor-phase copper overpressure during growth. Compared to h-BN films grown without a copper overpressure, this process results in a >10× reduction of 3-dimensional BN fullerene-like surface features, a reduction of carbon and oxygen contamination of 65% and 62%, respectively, an increase in h-BN grain size of >2×, and an 89% increase in electrical breakdown strength.

We report the photoresponse of a hydrogenated graphene (H-graphene)-based infrared (IR) photodetector that is 4 times higher than that of pristine graphene. An enhanced photoresponse in H-graphene is attributed to the longer photoinduced carrier lifetime and hence a higher internal quantum efficiency of the device. Moreover, a variation in the angle of incidence of IR radiation demonstrated a nonlinear photoresponse of the detector, which can be attributed to the photon drag effect. However, a linear dependence of the photoresponse is revealed with different incident powers for a given angle of IR incidence. This study presents H-graphene as a tunable photodetector for advanced photoelectronic devices with higher responsivity. In addition, in situ tunability of the graphene bandgap enables achieving a cost-effective technique for developing photodetectors without involving any external treatments.

Here we present a new approach to improve fixation of radionuclides on contaminated surfaces and eliminate their migration after nuclear accidents. The approach consists in fabrication of latex composite coatings, which combine properties of polymeric dust-suppressors preventing radionuclides migration with aerosols and selective inorganic sorbents blocking radionuclides leaching under contact with ground waters and atmospheric precipitates. Latex/cobalt hexacyanoferrate(II) (CoHCF) composites selective to cesium radionuclides were synthesized via “in situ” growth of CoHCF crystal on the surface of carboxylic or amino latexes using surface functional groups as ion-exchange centers for binding precursor ions Co²⁺ and [Fe(CN)₆]^4–. Casting such composite dispersions with variable content of CoHCF on ¹³⁷Cs-contaminated sand has yielded protective coatings, which reduced cesium leaching to 0.4% compared to 70% leaching through original latex coatings. ¹³⁷Cs migration from the sand surface was efficiently minimized when the volume fraction of CoHCF in the composite film was as low as 0.46–1.7%.

Detecting conformational change in protein or peptide is imperative in understanding their dynamic function and diagnosing diseases. Existing techniques either rely on ensemble average that lacks the necessary sensitivity or require florescence labeling. Here we propose to discriminate between different protein conformations with multiple layers of graphene nanopore sensors by measuring the effect of protein-produced electrostatic potential (EP) on electric transport. Using conformations of the octapeptide Angiotensin II obtained through molecular dynamics simulations, we show that the EP critically depends on the geometries of constituent atoms and each conformation carries a unique EP signature. We then, using quantum transport simulations, reveal that these characteristic EP profiles cause distinctive modulation to electric charge densities of the graphene nanopores, leading to distinguishable changes in conductivity. Our results open the potential of label-free, single-molecule, and real-time detection of protein conformational changes.

In this work, a novel wet silicon (Si) etching method, electric bias-attenuated metal-assisted chemical etching (EMaCE), is demonstrated to be readily available for three-dimensional (3D) electronic integration, microelectromechinal systems, and a broad range of 3D electronic components with low cost. On the basis of the traditional metal-assisted chemical etching process, an electric bias was applied to the Si substrate in EMaCE. The 3D geometry of the etching profile was effectively controlled by the bias in a real-time manner. The reported method successfully fabricated an array of over 10 000 vertical holes with diameters of 28 μm on 1 cm² silicon chips at a rate of up to 11 μm/min. The sidewall roughness was kept below 50 nm, and a high aspect ratio of over 10:1 was achieved. The 3D geometry could be attenuated by the variable applied bias in real time. Vertical deep etching was realized on (100)-, (111)-Si, and polycrystalline Si substrates. Complex features with lateral dimensions of 0.8–500 μm were also fabricated with submicron accuracy.

Two different soft-chemical, self-assembly-based solution approaches are employed to grow zinc oxide (ZnO) nanorods with controlled texture. The methods used involve seeding and growth on a substrate. Nanorods with various aspect ratios (1–5) and diameters (15–65 nm) are grown. Obtaining highly oriented rods is determined by the way the substrate is mounted within the chemical bath. Furthermore, a preheat and centrifugation step is essential for the optimization of the growth solution. In the best samples, we obtain ZnO nanorods that are almost entirely oriented in the (002) direction; this is desirable since electron mobility of ZnO is highest along this crystallographic axis. When used as the buffer layer of inverted organic photovoltaics (I-OPVs), these one-dimensional (1D) nanostructures offer: (a) direct paths for charge transport and (b) high interfacial area for electron collection. The morphological, structural, and optical properties of ZnO nanorods are studied using scanning electron microscopy, X-ray diffraction, and ultraviolet–visible light (UV-vis) absorption spectroscopy. Furthermore, the surface chemical features of ZnO films are studied using X-ray photoelectron spectroscopy and contact angle measurements. Using as-grown ZnO, inverted OPVs are fabricated and characterized. For improving device performance, the ZnO nanorods are subjected to UV-ozone irradiation. UV-ozone treated ZnO nanorods show: (i) improvement in optical transmission, (ii) increased wetting of active organic components, and (iii) increased concentration of Zn–O surface bonds. These observations correlate well with improved device performance. The devices fabricated using these optimized buffer layers have an efficiency of ∼3.2% and a fill factor of 0.50; this is comparable to the best I-OPVs reported that use a P3HT-PCBM active layer.

Attaching thiolated DNA on gold nanoparticles (AuNPs) has been extremely important in nanobiotechnology because DNA–AuNPs combine the programmability and molecular recognition properties of the biopolymers with the optical, thermal, and catalytic properties of the inorganic nanomaterials. However, current standard protocols to attach thiolated DNA on AuNPs involve time-consuming, tedious steps and do not perform well for large AuNPs, thereby greatly restricting applications of DNA–AuNPs. Here we demonstrate a rapid and facile strategy to attach thiolated DNA on AuNPs based on the excellent stabilization effect of mPEG-SH on AuNPs. AuNPs are first protected by mPEG-SH in the presence of Tween 20, which results in excellent stability of AuNPs in high ionic strength environments and extreme pHs. A high concentration of NaCl can be applied to the mixture of DNA and AuNP directly, allowing highly efficient DNA attachment to the AuNP surface by minimizing electrostatic repulsion. The entire DNA loading process can be completed in 1.5 h with only a few simple steps. DNA-loaded AuNPs are stable for more than 2 weeks at room temperature, and they can precisely hybridize with the complementary sequence, which was applied to prepare core–satellite nanostructures. Moreover, cytotoxicity assay confirmed that the DNA–AuNPs synthesized by this method exhibit lower cytotoxicity than those prepared by current standard methods. The proposed method provides a new way to stabilize AuNPs for rapid and facile loading thiolated DNA on AuNPs and will find wide applications in many areas requiring DNA–AuNPs, including diagnosis, therapy, and imaging.

We report for the first time the synthesis of monoclinic WO₃ quantum dots. A solvothermal processing at 250 °C in oleic acid of W chloroalkoxide solutions was employed. It was shown that the bulk monoclinic crystallographic phase is the stable one even for the nanosized regime (mean size 4 nm). The nanocrystals were characterized by X-ray diffraction, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–vis, Fourier transform infrared and Raman spectroscopy. It was concluded that they were constituted by a core of monoclinic WO₃, surface covered by unstable W(V) species, slowly oxidized upon standing in room conditions. The WO₃ nanocrystals could be easily processed to prepare gas-sensing devices, without any phase transition up to at least 500 °C. The devices displayed remarkable response to both oxidizing (nitrogen dioxide) and reducing (ethanol) gases in concentrations ranging from 1 to 5 ppm and from 100 to 500 ppm, at low operating temperatures of 100 and 200 °C, respectively. The analysis of the electrical data showed that the nanocrystals were characterized by reduced surfaces, which enhanced both nitrogen dioxide adsorption and oxygen ionosorption, the latter resulting in enhanced ethanol decomposition kinetics.

Concentration gradients of guidance molecules influence cell behavior and growth in biological tissues and are therefore of interest for the design of biomedical scaffolds for regenerative medicine. We developed an electrospining method to generate a dual-gradient of bioactive molecules and fiber density along electrospun nanofibers without any post spinning treatment. Functionalization with fluorescent molecules demonstrated the efficiency of the method to generate a discontinuous concentration gradient along the aligned fibers. As a proof of concept for tissue engineering, the silk nanofibers were functionalized with increasing concentrations of nerve growth factor (NGF) and the biological activity was assessed and quantified with rat dorsal root ganglion (DRG) neurons cultures. Protein assays showed the absence of passive release of NGF from the functionalized fibers. The results demonstrated that the NGF concentration gradient led to an oriented and increased growth of DRG neurons (417.6 ± 55.7 μm) compared to a single uniform NGF concentration (264.5 ± 37.6 μm). The easy-to-use electrospinning technique combined with the multiple molecules that can be used for fiber functionalization makes this technique versatile for a broad range of applications from biosensors to regenerative medicine.

Natural materials consisting of protein structures impregnated with a tiny amount of metals often exhibit impressive mechanical behavior, which represents a new design paradigm for the development of biomimetic materials. Here, we produced Al-infiltrated silks by applying a modified Al₂O₃ atomic layer deposition process to the dragline silk of the Nephila pilipes spider, which showed unusual mechanical properties. The deformation behavior of the molecular structure of the Al-infiltrated silk was investigated by performing in situ Raman spectroscopy, where Raman shifts were measured concurrently with macroscopic mechanical deformations. For identifying the role of the infiltrated Al atoms, the study was performed in parallel with untreated silk, and the results were compared. Our experimental results revealed that superior mechanical properties of the Al-infiltrated silk are likely to be caused by the alterations of the sizes of the β-sheet crystals and their distribution.

Synthesis of two-dimensional (2D) metal chalcogenide based half-metallic nanosheets is in high demand for modern electronics and spintronics applications. Herein, we predict from first-principles calculations that the 2D heterostructure Co/MoS₂, consisting of a monolayer of Co atoms deposited on a single MoS₂ sheet, possesses robust ferromagnetic and half-metallic features and exhibits 100% spin-filter efficiency within a broad bias range. Its ferromagnetic and half-metallic nature persists even when overlaid with a graphene sheet. Because of the relatively strong surface binding energy and low clustering ratio of Co atoms on the MoS₂ surface, we predict that the heterostructure is synthesizable via wetting deposition of Co on MoS₂ by electron-beam evaporation technique. Our work strongly suggests Co/MoS₂ as a compelling and feasible candidate for highly effective information and high-density memory devices.

Magnetic mesoporous γ-Fe₂O₃@Ti_0.9Si_0.1O₂ (abbreviated as Fe@TiSi) core–shell nanofibers were prepared using sol–gel chemistry combined with coaxial-electrospinning technology by adjusting the inner and outer feed ratios. The properties of these novel core–shell nanofibers were characterized by SEM, HRTEM, XRD, FTIR, BET, XPS, and UV–vis spectra. To evaluate the chemical properties of the nanofibers for cleaning typical organic wastewater, methylene blue (MB) was used as a target organic pollutant and was cleaned under irradiation with sunlight and visible light. The Fe@TiSi hierarchical nanofibers composed of a 1:10 feed ratio displayed a mesoporous structure and showed the highest photocatalytic activity for the degradation of MB in water. Furthermore, 86.8% and 71.1% of the MB, which was added at an original concentration of 1 mg/L, was removed after 60 min of irradiation with sunlight and visible light in the presence of Fe@TiSi at a concentration of 0.2 g/L, and 100% of the MB was removed after 75 min. It is very important that the magnetic nanofibers could be recycled rapidly with an outside magnet, and the actual water treatment process was easy to achieve. Moreover, the mechanism of MB degradation by Fe@TiSi core–shell nanofibers was proposed.

Cellulose microbeads can be used as immobilization supports. We report on the design and preparation of magneto-responsive cellulose microbeads and microcapsules by self-assembled shells of cellulose nanocrystals (CNC) carrying magnetic CoFe₂O₄ nanoparticles, that is, a mixture of isotropic and anisotropic nanomaterials. The magnetic CNCs formed a structured layer, a mesh, consisting of CNCs and magnetic particles bound together on the surface of distinct droplets of hexadecane and styrene dispersed in water. Because of the presence of CNCs the highly crystalline mesh was targeted to provide an improved barrier property of the microbead shell compared to neat polymer shells, while the magnetic particles provided the magnetic response. In situ polymerization of the styrene phase led to the formation of solid microbeads (∼8 μm diameter) consisting of polystyrene (PS) cores encapsulated in the magnetic CNC shells (shell-to-core mass ratio of 4:96). The obtained solid microbeads were ferromagnetic (saturation magnetization of ∼60 emu per gram of the magnetic phase). The magnetic functionality enables easy separation of substances immobilized on the beads. Such a functionality was tested in removal of a dye from water. The microbeads were further utilized to synthesize hollow microcapsules by solubilization of the PS core. The CNC-based, magneto-responsive solid microbeads and hollow microcapsules were characterized by electron microscopy (morphology), X-ray diffraction (phase composition), and magnetometry (magnetic properties). Such hybrid systems can be used in the design of materials and devices for application in colloidal stabilization, concentration, separation, and delivery, among others.

New TiO₂/WO₃ films were produced by the layer-by-layer (LbL) technique and successfully applied as self-cleaning photocatalytic surfaces. The films were deposited on fluorine doped tin oxide (FTO) glass substrates from the respective metal oxide nanoparticles obtained by the sol–gel method. Thirty alternative immersions in pH = 2 TiO₂ and pH = 10 WO₃ sols resulted in ca. 400 nm thick films that exhibited a W(VI)/Ti(IV) molar ratio of 0.5, as determined by X-ray photoelectron spectroscopy. Scanning electron microscopy, along with atomic force images, showed that the resulting layers are constituted by aggregates of very small nanoparticles (<20 nm) and exhibited nanoporous and homogeneous morphology. The electronic and optical properties of the films were investigated by UV–vis spectrophotometry and ultraviolet photoelectron spectroscopy. The films behave as nanoscale heterojunctions, and the presence of WO₃ nanoparticles caused a decrease in the optical band gap of the bilayers compared to that of pure LbL TiO₂ films. The TiO₂/WO₃ thin films exhibited high hydrophilicity, which is enhanced after exposition to UV light, and they can efficiently oxidize gaseous acetaldehyde under UV(A) irradiation. Photonic efficiencies of ξ = 1.5% were determined for films constituted by 30 TiO₂/WO₃ bilayers in the presence of 1 ppm of acetaldehyde, which are ∼2 times higher than those observed for pure LbL TiO₂ films. Therefore, these films can act as efficient and cost-effective layers for self-cleaning, antifogging applications.

Monodispersed Mn_xZn_1–xFe₂O₄ magnetic nanoparticles of 8 nm are synthesized and encapsulated in amphiphilic block copolymer for development of the hydrophilic magnetic nanoclusters (MNCs). These MNCs exhibit superparamagnetic characteristics, high specific absorption rate (SAR), large saturation magnetization (M_s), excellent stability, and good biocompatibility. MnFe₂O₄ and Mn_0.6Zn_0.4Fe₂O₄ are selected as optimum compositions for the MNCs (MnFe₂O₄/MNC and Mn_0.6Zn_0.4Fe₂O₄/MNC) and employed for magnetic fluid hyperthermia (MFH) in vitro. To ensure biosafety of MFH, the parameters of alternating magnetic field (AMF) and exposure time are optimized with low frequency, f, and strength of applied magnetic field, H_applied. Under optimized conditions, MFH of MnFe₂O₄/MNC and Mn_0.6Zn_0.4Fe₂O₄/MNC result in cancer cell death rate up to 90% within 15 min. The pathway of cancer cell death is identified as apoptosis, which occurs in mild hyperthermia near 43 °C. Both MnFe₂O₄/MNC and Mn_0.6Zn_0.4Fe₂O₄/MNC show similar efficiencies on drug-sensitive and drug-resistant cancer cells. On the basis of these findings, those Mn_xZn_1–xFe₂O₄ nanoclusters can serve as a promising candidate for effective targeting, diagnosis, and therapy of cancers. The multimodal cancer treatment is also possible as amphiphilic block copolymer can encapsulate, in a similar fashion, different nanoparticles, hydrophobic drugs, and other functional molecules.

Molecular layer deposition (MLD) of the hafnium alkoxide polymer known as “hafnicone” was grown using sequential exposures of tetrakis(dimethylamido) hafnium (TDMAH) and ethylene glycol (EG) as the reactants. In situ quartz crystal microbalance (QCM) experiments demonstrated self-limiting reactions and linear growth versus the number of TDMAH/EG reaction cycles. Ex situ X-ray reflectivity (XRR) analysis confirmed linear growth and measured the density of the hafnicone films. The hafnicone growth rates were temperature-dependent and decreased from 1.2 Å per cycle at 105 °C to 0.4 Å per cycle at 205 °C. The measured density was ∼3.0 g/cm³ for the hafnicone films at all temperatures. Transmission electron microscopy images revealed very uniform and conformal hafnicone films. The XRR studies also showed that the hafnicone films were very stable with time. Nanoindentation measurements determined that the elastic modulus and hardness of the hafnicone films were 47 ± 2 and 2.6 ± 0.2 GPa, respectively. HfO₂/hafnicone nanolaminate films also were fabricated using HfO₂ atomic layer deposition (ALD) and hafnicone MLD at 145 °C. The in situ QCM measurements revealed that HfO₂ ALD nucleation on the hafnicone MLD surface required at least 18 TDMAH/H₂O cycles. Hafnicone alloys were also fabricated by combining HfO₂ ALD and hafnicone MLD at 145 °C. The composition of the hafnicone alloy was varied by adjusting the relative number of TDMAH/H₂O ALD cycles and TDMAH/EG MLD cycles in the reaction sequence. The electron density changed continuously from 8.2 × 10²³ e^–/cm³ for pure hafnicone MLD films to 2.4 × 10²⁴ e^–/cm³ for pure HfO₂ ALD films. These hafnicone films and the HfO₂/hafnicone nanolaminates and alloys may be useful for flexible thin-film devices.

In this study, Li-rich cathode, 0.4Li₂MnO₃·0.6LiNi_1/3Co_1/3Mn_1/3O₂ was synthesized by a resorcinol formaldehyde assisted sol–gel method for the first time. Then, the surface of the as-prepared Li-rich cathode was modified with different amounts of LiNi_0.5Mn_1.5O₄ (5, 10, and 20 wt %) through a simple dip-dry approach. The structural and electrochemical characterizations revealed that the spinel LiNi_0.5Mn_1.5O₄ coating not only can prevent electrolytes from eroding the Li-rich core but also can facilitate fast lithium ion transportation. As a result, the 20 wt % coated sample delivered an initial discharge capacity of 298.6 mAh g^–1 with a Coulombic efficiency of 84.8%, compared to 281.1 mAh g^–1 and 70.2%, respectively, for the bare sample. Particularly, the coated sample demonstrates a Li storage capacity of 170.7 mAh g^–1 and capacity retention of 94.4% after 100 cycles at a high rate of 5 C (1250 mA g^–1), showing a prospect for practical lithium battery applications. More significantly, the synthetic method proposed in this work is facile and low-cost and possibly could be adopted for large-scale production of surface-modified cathode materials.

Stimuli responsive polymeric nanocarrier (RCOP-2) functionalized with frontline antituberculosis drug (Rifampicin) is demonstrated for sustained release. Bioavailability of Rifampicin is taken care of by conjugating this drug through a acylhydrazine linker to the polymeric backbone. The poly(ethylene glycol) structural motif is introduced in the copolymer architecture for water solubility. Releasing retinal along with Rifampicin is hypothesized to reduce the risk of side effects due to Rifampicin. The self-assembly of RCOP-2, due to the amphiphilicity present in the copolymer, is explored in detail. The pH responsiveness of RCOP-2 is demonstrated in mild acidic environment as well as in cell lines. The 4T cell line, due to its acidic nature, shows time-dependent cellular internalization. On the basis of the results, our unique design is expected to provide an increased bioavalaibility of Rifampicin with reduced side effects. From the flow cytometry results on A549 cell lines, it is clear that the newly designed copolymer RCOP-2 can internalize efficiently and serve as an effective Rifampicin delivery system.

In an effort to reduce the flammability of polyurethane foam, a thin film of renewable inorganic nanoparticles (i.e., anionic vermiculite [VMT] and cationic boehmite [BMT]) was deposited on polyurethane foam via layer-by-layer (LbL) assembly. One, two, and three bilayers (BL) of BMT-VMT resulted in foam with retained shape after being exposed to a butane flame for 10 s, while uncoated foam was completely consumed. Cone calorimetry confirmed that the coated foam exhibited a 55% reduction in peak heat release rate with only a single bilayer deposited. Moreover, this protective nanocoating reduced total smoke release by 50% relative to untreated foam. This study revealed that 1 BL, adding just 4.5 wt % to PU foam, is an effective and conformal flame retardant coating. These results demonstrate one of the most efficient and renewable nanocoatings prepared using LbL assembly, taking this technology another step closer to commercial viability.

Dual clickable nanospheres (DCNSs) were synthesized in one step using an efficient approach of ultrasonic-assisted azide–alkyne click polymerization, avoiding the need of surfactants. This novel approach presents a direct clickable monomer-to-nanosphere synthesis. Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and dynamic laser scattering (DLS) were used to characterize the synthesized DCNSs. Numerous terminal alkynyl and azide groups on the surface of DCNSs facilitate effective conjugation of multiple molecules or ligands onto a single nanocarrier platform under mild conditions. To exemplify the potential of DCNSs in biological applications, (1) multivalent glyconanoparticles (GNPs) were prepared by clicking DCNSs with azide-functionalized and alkyne-functionalized lactose sequentially for the determination of carbohydrate-galectin interactions with quartz crystal microbalance (QCM) biosensor. Using protein chip (purified galectin-3 coated on chip) and cell chip (Jurkat cells immobilized on chip), the QCM sensorgrams showed excellent binding activity of GNPs for galectins; (2) fluorescent GNPs were prepared by clicking DCNSs with azide-functionalized Rhodamine B and alkyne-functionalized lactose sequentially in order to target galectin, which is overexpressed on the surface of Jurkat cells. The fluorescent images obtained clearly showed the cellular internalization of fluorescent GNPs. This fluorescent probe could be easily adapted to drugs to construct lectin-targeted drug delivery systems. Thus, DCNSs prepared with our method may provide a wide range of potential applications in glycobiology and biomedicine.

Calcium phosphate-based nanocomposites offer a unique solution toward producing scaffolds for orthopedic and dental implants. However, despite attractive bioactivity and biocompatibility, hydroxyapatite (HAp) has been limited in heavy load-bearing applications due to its intrinsically low mechanical strength. In this work, to improve the mechanical properties of HAp, we grew HAp nanoplates from the surface of one-dimensional titania nanorod structures by combining a coprecipitation and sol–gel methodology using supercritical fluid processing with carbon dioxide (scCO₂). The effects of metal alkoxide concentration (1.1–1.5 mol/L), reaction temperature (60–80 °C), and pressure (6000–8000 psi) on the morphology, crystallinity, and surface area of the resulting nanostructured composites were examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and Brunauer–Emmet–Teller (BET) method. Chemical composition of the products was characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near-edge structure (XANES) analyses. HAp nanoplates and HAp–TiO₂ nanocomposites were homogeneously mixed within poly(ε-caprolactone) (PCL) to develop scaffolds with enhanced physical and mechanical properties for bone regeneration. Mechanical behavior analysis demonstrated that the Young’s and flexural moduli of the PCL/HAp–TiO₂ composites were substantially higher than the PCL/HAp composites. Therefore, this new synthesis methodology in scCO₂ holds promise for bone tissue engineering with improved mechanical properties.

A new methylol and methyl functionalized metal–organic frameworks (MOFs) QI-Cu has been designed and synthesized. As a variant of NOTT-101, this material exhibits excellent CO₂ uptake capacities at ambient temperature and pressure, as well as high CH₄ uptake capacities. The CO₂ uptake for QI-Cu is high, up to 4.56 mmol g^–1 at 1 bar and 293 K, which is top-ranked among MOFs for CO₂ adsorption and significantly larger than the nonfunctionalized NOTT-101 of 3.93 mmol g^–1. The enhanced isosteric heat values of CO₂ and CH₄ adsorption were also obtained for this linker functionalized MOFs. From the single-component adsorption isotherms, multicomponent adsorption was predicted using the ideal adsorbed solution theory (IAST). QI-Cu shows an improvement in adsorptive selectivity of CO₂ over CH₄ and N₂ below 1 bar. The incorporation of methylol and methyl groups also greatly improves the hydrostability of the whole framework.

The effects of ZnO on graphene oxide (GO)–ZnO nanocomposites are investigated to tune the conductivity in GO under field effect regime. Zinc oxides with different concentrations from 5 wt % to 25 wt % are used in a GO matrix to increase the conductivity in the composite. Six sets of field effect transistors with pristine GO and GO–ZnO as the channel layer at varying ZnO concentrations were fabricated. From the transfer characteristics, it is observed that GO exhibited an insulating behavior and the transistors with low ZnO (5 wt %) concentration initially showed p-type conductivity that changes to n-type with increases in ZnO loading. This n-type dominance in conductivity is a consequence of the transfer of electrons from ZnO to the GO matrix. From X-ray photoelectron spectroscopic measurements, it is observed that the progressive reduction in the C–OH oxygen group took place with increases in ZnO loading. Thus, from insulating GO to p- and then n-type, conductivity in GO could be achieved with reduction in the C–OH oxygen group by photocatalytic reduction of GO with varying degrees of ZnO. The restoration of sp² electron network in the GO matrix with the anchoring of ZnO nanostructures was observed from Raman spectra. From UV–visible spectra, the band gap in pristine GO was found to be 3.98 eV and reduced to 2.8 eV with increase in ZnO attachment.

Iron oxide nanoparticles dispersed within a thermally responsive poly(N-isopropylacrylamide) (PNIPAm) hydrogel matrix effectively convert the photo energy of visible light of modest intensity into thermal energy, providing the efficient means to trigger changes in volumetric swelling of hydrogels. However, long irradiation time (on the order of minutes) and modest volume change limit their applications that need fast response and/or large volume change. In this work, we found that the degree of volume change triggered by light could be maximized by adjusting the lower critical solution temperature (LCST) of the hydrogels. On the basis of the evidence in this investigation, we can develop highly responsive hydrogels that show rapid and significant light-induced volume change, which could be achieved by incorporating a hydrophobic N,N-diethylacrylamide moiety in the PNIPAm network. This enhanced responsiveness led to the successful application of this material in a remote-controllable microvalve for microfluidic devices operated by light illumination within a few seconds.

In this paper, we report and discuss our successful synthesis of monodispersed, polystyrene-coated gold core–shell nanoparticles (Au@PS NPs) for use in highly efficient, air-stable, organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). These core–shell NPs retain the dual functions of (1) the plasmonic effect of the Au core and (2) the stability and solvent resistance of the cross-linked PS shell. The monodispersed Au@PS NPs were incorporated into a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film that was located between the ITO substrate and the emitting layer (or active layer) in the devices. The incorporation of the Au@PS NPs provided remarkable improvements in the performances of both OLEDs and OPVs, which benefitted from the plasmonic effect of the Au@PS NPs. The OLED device with the Au@PS NPs achieved an enhancement of the current efficiency that was 42% greater than that of the control device. In addition, the power conversion efficiency was increased from 7.6% to 8.4% in PTB7:PC₇₁BM-based OPVs when the Au@PS NPs were embedded. Direct evidence of the plasmonic effect on optical enhancement of the device was provided by near-field scanning optical microscopy measurements. More importantly, the Au@PS NPs induced a remarkable and simultaneous improvement in the stabilities of the OLED and OPV devices by reducing the acidic and hygroscopic properties of the PEDOT:PSS layer.

Au nanostructures as catalysts toward electrooxidation of small molecules generally suffer from ultralow surface adsorption capability and stability. Here, we report Ni(OH)₂ layer decorated nanoporous (NP) AuNi alloys with a three-dimensional and bimodal porous architecture, which are facilely fabricated by a combination of chemical dealloying and in situ surface segregation, for the enhanced electrocatalytic performance in biosensors. As a result of the self-grown Ni(OH)₂ on the AuNi alloys with a coherent interface, which not only enhances adsorption energy of Au and electron transfer of AuNi/Ni(OH)₂ but also prohibits the surface diffusion of Au atoms, the NP composites are enlisted to exhibit significant enhancement in both electrocatalytic activity and stability toward glucose electrooxidation. The highly reliable glucose biosensing with exceptional reproducibility and selectivity as well as quick response makes it a promising candidate as electrode materials for the application in nonenzymatic glucose biosensors.

Enzyme-linked immunosorbent assay (ELISA) provides a convenient means for the detection of Salmonella enterica serovar Typhimurium (STM), which is important for rapid diagnosis of foodborne pathogens. However, conventional ELISA is limited by antibody–antigen immunoreactions and suffers from poor sensitivity and tedious sample pretreatment. Therefore, development of novel ELISA remains challenging. Herein, we designed a comprehensive strategy for rapid, sensitive, and quantitative detection of STM with high specificity by gold nanoparticle-based enzyme-linked antibody-aptamer sandwich (nano-ELAAS) method. STM was captured and preconcentrated from samples with aptamer-modified magnetic particles, followed by binding with detector antibodies. Then nanoprobes carrying a large amount of reporter antibodies and horseradish peroxidase molecules were used for colorimetric signal amplification. Under the optimized reaction conditions, the nano-ELAAS assay had a quantitative detection range from 1 × 10³ to 1 × 10⁸ CFU mL^–1, a limit of detection of 1 × 10³ CFU mL^–1, and a selectivity of >10-fold for STM in samples containing other bacteria at higher concentration with an assay time less than 3 h. In addition, the developed nanoprobes were improved in terms of detection range and/or sensitivity when compared with two commercial enzyme-labeled antibody signal reporters. Finally, the nano-ELAAS method was demonstrated to work well in milk samples, a common source of STM contamination.

A synthetic mimic of mussel adhesive protein, dopamine-modified four-armed poly(ethylene glycol) (PEG-D4), was combined with a synthetic nanosilicate, Laponite (Na^0.7+(Mg_5.5Li_0.3Si₈)O₂₀(OH)₄)^0.7–), to form an injectable naoncomposite tissue adhesive hydrogel. Incorporation of up to 2 wt % Laponite significantly reduced the cure time while enhancing the bulk mechanical and adhesive properties of the adhesive due to strong interfacial binding between dopamine and Laponite. The addition of Laponite did not alter the degradation rate and cytocompatibility of PEG-D4 adhesive. On the basis of subcutaneous implantation in rat, PEG-D4 nanocomposite hydrogels elicited minimal inflammatory response and exhibited an enhanced level of cellular infiltration as compared to Laponite-free samples. The addition of Laponite is potentially a simple and effective method for promoting bioactivity in a bioinert, synthetic PEG-based adhesive while simultaneously enhancing its mechanical and adhesive properties.

Sulfonated polyimide (SPI)/sulfonated propylsilane graphene oxide (SPSGO) was assessed to be a promising candidate for polymer electrolyte membranes (PEMs). Incorporation of multifunctionalized (-SO₃H and -COOH) SPSGO in SPI matrix improved proton conductivity and thermal, mechanical, and chemical stabilities along with bound water content responsible for slow dehydration of the membrane matrix. The reported SPSGO/SPI composite PEM was designed to promote internal self-humidification, responsible for water-retention properties, and to promote proton conduction, due to the presence of different acidic functional groups. Strong hydrogen bonding between multifunctional groups thus led to the presence of interconnected hydrophobic graphene sheets and organic polymer chains, which provides hydrophobic–hydrophilic phase separation and suitable architecture of proton-conducting channels. In single-cell direct methanol fuel cell tests, SPI/SPSGO-8 exhibited 75.06 mW·cm^–2 maximum power density (in comparison with commercial Nafion 117 membrane, 62.40 mW·cm^–2) under 2 M methanol fuel at 70 °C.

Reduced graphene oxide (rGO) sheets were self-assembled onto the surfaces of electrospun polymer nanofibers to form an ultrathin coating. These rGO/polymer composite nanofibers were used to fabricate nitrogen dioxide (NO₂) sensor. This sensor can be performed at room temperature, and it exhibited a high sensitivity of 1.03 ppm^–1 with excellent selectivity and good reversibility. Furthermore, the limit of detection was experimentally measured to be as low as 150 ppb, and this value is much lower than the threshold exposure limit proposed by American Conference of Governmental Industrial Hygienists (200 ppb).

Hollow fiber nanofiltration membranes can withstand much higher foulant concentrations than their spiral wound counterparts and can be used in water purification without pretreatment. Still, the preparation of hollow fiber nanofiltration membranes is much less established. In this work, we demonstrate the design of a hollow fiber nanofiltration membrane with excellent rejection properties by alternatively coating a porous ultrafiltration membrane with a polycation, a polyzwitterion, and a polyanion. On model surfaces, we show, for the first time, that the polyzwitterion poly N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium betaine (PSBMA) can be incorporated into traditional polyelectrolyte multilayers based on poly(styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC). Furthermore, work on model surfaces allows a good characterization of, and insight into, the layer build-up and helps to establish the optimal membrane coating conditions. Membranes coated with these multilayers have high salt rejection of up to 42% NaCl, 72% CaCl₂, and 98% Na₂SO₄ with permeabilities of 3.7–4.5 l·m^–2·h^–1·bar^–1. In addition to the salt rejections, the rejection of six distinctively different micropollutants, with molecular weights between 215 and 362 g·mol^–1, was investigated. Depending on the terminating layer, the incorporation of the polyzwitterion in the multilayer results in nanofiltration membranes that show excellent retentions for both positively and negatively charged micropollutants, a behavior that is attributed to dielectric exclusion of the solutes. Our approach of combining model surfaces with membrane performance measurements provides unique insights into the properties of polyzwitterion-containing multilayers and their applications.

Ionic liquids (ILs) have received considerable interest for use in electrostatic gating in complex oxide systems. Understanding the ionic liquid/oxide interface, and any bias-induced electrochemical degradation, is critical for the interpretation of transport phenomena. The integrity of the interface between ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate and La_1/3Sr_2/3FeO₃ under various biasing conditions was examined by analytical transmission electron microscopy, and we report film degradation in the form of an irreversible chemical reaction regardless of the applied bias. This results in an intermixing region of 4–6 nm at the IL/oxide interface. Electron energy loss spectroscopy shows La and Fe migration into the ionic liquid, resulting in secondary phase formation under negative bias. Our approach can be extended to other ionic liquid/oxide systems in order to better understand the electrochemical stability window of these device structures.

The coaddition of KH and RbH significantly improves the hydrogen storage properties of the Mg(NH₂)₂-2LiH system. An Mg(NH₂)₂-2LiH-0.04KH-0.04RbH composite was able to reversibly store 5.2 wt % H₂ when the dehydrogenation operates at 130 °C and the hydrogenation operates at 120 °C. The isothermal dehydrogenation rate at 130 °C was approximately 43 times that of a pristine sample. During ball-milling, KH reacts with RbH to form a K(Rb)H solid solution. Upon heating, RbH first separates from the K(Rb)H solid solution and participates in the first step of dehydrogenation reaction, and then the remaining KH participates in the second dehydrogenation reaction. The presence of RbH and KH provide synergetic effects, which improve the thermodynamics and kinetics of hydrogen storage in the Mg(NH₂)₂-2LiH system. In particular, more than 93% of the hydrogen storage capacity (4.4 wt %) remains after cycling a sample with 0.04 mol of KH and RbH for 50 cycles, indicating notably better cycling stability compared with any presently known Li–Mg–N–H systems.

Tonsil-derived mesenchymal stem cells (TMSCs) were investigated for hepatogenic differentiation in the 3D matrixes of poly(ethylene glycol)-b-poly(l-alanine) (PEG-L-PA) thermogel. The diblock polymer formed β-sheet based fibrous nanoassemblies in water, and the aqueous polymer solution undergoes sol-to-gel transition as the temperature increases in a concentration range of 5.0–8.0 wt %. The cell-encapsulated 3D matrix was prepared by increasing the temperature of the cell-suspended PEG-L-PA aqueous solution (6.0 wt %) to 37 °C. The gel modulus at 37 °C was about 1000 Pa, which was similar to that of decellularized liver tissue. Cell proliferation, changes in cell morphology, hepatogenic biomarker expressions, and hepatocyte-specific biofunctions were compared for the following 3D culture systems: TMSC-encapsulated thermogels in the absence of hepatogenic growth factors (protocol M), TMSC-encapsulated thermogels where hepatogenic growth factors were supplied from the medium (protocol MGF), and TMSC-encapsulated thermogels where hepatogenic growth factors were coencapsulated with TMSCs during the sol-to-gel transition (protocol GGF). The spherical morphology and size of the encapsulated cells were maintained in the M system during the 3D culture period of 28 days, whereas the cells changed their morphology and significant aggregation of cells was observed in the MGF and GGF systems. The hepatocyte-specific biomarker expressions and metabolic functions were negligible for the M system. However, hepatogenic genes of albumin, cytokeratin 18 (CK-18), and hepatocyte nuclear factor 4α (HNF 4α) were significantly expressed in both MGF and GGF systems. In addition, production of albumin and α-fetoprotein was also significantly observed in both MGF and GGF systems. The uptake of cardiogreen and low-density lipoprotein, typical metabolic functions of hepatocytes, was apparent for MGF and GGF. The above data indicate that the 3D culture system of PEG-L-PA thermogels provides cytocompatible microenvironments for hepatogenic differentiation of TMSCs. In particular, the successful results of the GGF system suggest that the PEG-L-PA thermogel can be a promising injectable tissue engineering system for liver tissue regeneration after optimizing the aqueous formulation of TMSCs, hepatogenic growth factors, and other biochemicals.

A novel series of aromatic block copolymers composed of fluorinated phenylene and biphenylene groups and diphenyl ether (QPE-bl-5) or diphenyl sulfide (QPE-bl-6) groups as a scaffold for quaternized ammonium groups is reported. The block copolymers were synthesized via aromatic nucleophilic substitution polycondensation, chloromethylation, quaternization, and ion exchange reactions. The block copolymers were soluble in organic solvents and provided thin and bendable membranes by solution casting. The membranes exhibited well-developed phase-separated morphology based on the hydrophilic/hydrophobic block copolymer structure. The membranes exhibited mechanical stability as confirmed by DMA (dynamic mechanical analyses) and low gas and hydrazine permeability. The QPE-bl-5 membrane with the highest ion exchange capacity (IEC = 2.1 mequiv g^–1) exhibited high hydroxide ion conductivity (62 mS cm^–1) in water at 80 °C. A noble metal-free fuel cell was fabricated with the QPE-bl-5 as the membrane and electrode binder. The fuel cell operated with hydrazine as a fuel exhibited a maximum power density of 176 mW cm^–2 at a current density of 451 mA cm^–2.

One-dimensional anodic titanium oxide nanotube (TONT) arrays provide a direct pathway for charge transport, and thus hold great potential as working electrodes for electrochemical energy conversion and storage devices. However, the prominent surface recombination due to the large amount surface defects hinders the performance improvement. In this work, the surface states of TONTs were passivated by conformal coating of high-quality Al₂O₃ onto the tubular structures using atomic layer deposition (ALD). The modified TONT films were subsequently employed as anodes for photoelectrochemical (PEC) water splitting. The photocurrent (0.5 V vs Ag/AgCl) recorded under air mass 1.5 global illumination presented 0.8 times enhancement on the electrode with passivation coating. The reduction of surface recombination rate is responsible for the substantially improved performance, which is proposed to have originated from a decreased interface defect density in combination with a field-effect passivation induced by a negative fixed charge in the Al₂O₃ shells. These results not only provide a physical insight into the passivation effect, but also can be utilized as a guideline to design other energy conversion devices.

Antifog surfaces are necessary for any application requiring optical efficiency of transparent materials. Surface modification methods aimed toward increasing solid surface energy, even when supposed to be permanent, in fact result in a nondurable effect due to the instability in air of highly hydrophilic surfaces. We propose the strategy of combining a hydrophilic chemistry with a nanotextured topography, to tailor a long-lasting antifog modification on commercial transparent plastics. In particular, we investigated a two-step process consisting of self-masked plasma etching followed by plasma deposition of a silicon-based film. We show that the deposition of the silicon-based coatings on the flat (pristine) substrates allows a continuous variation of wettability from hydrophobic to superhydrophilic, due to a continuous reduction of carbon-containing groups, as assessed by Fourier transform infrared and X-ray photoelectron spectroscopies. By depositing these different coatings on previously nanotextured substrates, the surface wettability behavior is changed consistently, as well as the condensation phenomenon in terms of microdroplets/liquid film appearance. This variation is correlated with advancing and receding water contact angle features of the surfaces. More importantly, in the case of the superhydrophilic coating, though its surface energy decreases with time, when a nanotextured surface underlies it, the wetting behavior is maintained durably superhydrophilic, thus durably antifog.

Cobalt (Co)-doped MOF-5s (Co-MOF-5s) were first synthesized by a secondary growth method, followed by a heat treatment to yield Co-doped ZnO coated with carbon (CZO@C). Compared with carbon-coated ZnO (ZnO@C), the doping of Co increased the graphitization degree of the carbon on the surface of CZO@C nanoparticles and enhanced the conductivity of the material. The electrochemical properties of the materials were characterized by galvanostatic discharge/charge tests. It was found that the as-synthesized CZO@C composites enabled a reversible capacity of 725 mA h g^–1 up to the 50th cycle at a current density of 100 mA g^–1, which was higher than that of ZnO@C composites (335 mA h g^–1).

Here, we present an Au@Pt core–shell multibranched nanoparticle as a new substrate capable of in situ surface-enhanced Raman scattering (SERS), thereby enabling monitoring of the catalytic reaction on the active surface. By careful control of the amount of Pt deposited bimetallic Au@Pt, nanoparticles with moderate performance both for SERS and catalytic activity were obtained. The Pt-catalyzed reduction of 4-nitrothiophenol by borohydride was chosen as the model reaction. The intermediate during the reaction was captured and clearly identified via SERS spectroscopy. We established in situ SERS spectroscopy as a promising and powerful technique to investigate in situ reactions taking place in heterogeneous catalysis.

Surface-bound silver ions were demonstrated to be responsible for the antibacterial action of silver, silicon-containing hydroxyapatite (Ag,Si-HA). X-ray photoelectron spectroscopy, transmission electron microscopy, and induced coupled plasma spectroscopy results suggested that silver ions in the crystal structure diffused toward the crystal surface of Ag,Si-HA, and interacted with adherent Staphylococcus aureus bacteria, thus damaging the cell wall and inducing leakage of potassium ions. All these steps constitute the mechanism of antibacterial action for Ag,Si-HA. Consequently, Ag,Si-HA gave rise to a 7-log reduction of the adherent bacteria as compared to HA and Si-HA at 168 h. Silicon in Ag,Si-HA helped to mitigate the reduced effect of bone differentiation in Ag-HA as shown in the alkaline phosphatase, type I collagen and osteocalcin results, promoting enhanced biological response, without compromising the antibacterial property. On the whole, Ag,Si-HA containing an optimized content of 0.5 wt % silver and 0.7 wt % silicon provides antibacterial properties and enhanced biological response.

Hydrolysis–condensation of bis(triprop-1-ynylstannyl)butylene led to nanostructured bridged polystannoxane films yielding tin dioxide thin layers upon UV-treatment or annealing in air. According to Fourier transform infrared (FTIR) spectroscopy, contact angle measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) data, the films were composed of a network of aggregated “pseudo-particles”, as calcination at 600 °C is required to form cassiterite nanocrystalline SnO₂ particles. In the presence of reductive gases such as H₂ and CO, these films gave rise to highly sensitive, reversible, and reproducible responses. The best selectivity toward H₂ was reached at 150 °C with the hybrid thin films that do not show any response to CO at 20–200 °C. On the other hand, the SnO₂ films prepared at 600 °C are more sensitive to H₂ than to CO with best operating temperature in the 300–350 °C range. This organometallic approach provides an entirely new class of gas-sensing materials based on a class II organic–inorganic hybrid layer, along with a new way to include organic functionality in gas sensing metal oxides.

In this work, unique functional devices exhibiting controlled gradients of properties are fabricated by dip-coating process in acceleration mode. Through this new approach, thin films with “on-demand” thickness graded profiles at the submillimeter scale are prepared in an easy and versatile way, compatible for large-scale production. The technique is adapted to several relevant materials, including sol–gel dense and mesoporous metal oxides, block copolymers, metal–organic framework colloids, and commercial photoresists. In the first part of the Article, an investigation on the effect of the dip coating speed variation on the thickness profiles is reported together with the critical roles played by the evaporation rate and by the viscosity on the fluid draining-induced film formation. In the second part, dip-coating in acceleration mode is used to induce controlled variation of functionalities by playing on structural, chemical, or dimensional variations in nano- and microsystems. In order to demonstrate the full potentiality and versatility of the technique, original graded functional devices are made including optical interferometry mirrors with bidirectional gradients, one-dimensional photonic crystals with a stop-band gradient, graded microfluidic channels, and wetting gradient to induce droplet motion.

The mechanical failure at the electrode interfaces (laminate/current collector and binder/particle interfaces) leads to particle isolation and delamination, which has been regarded as one of the main reasons for the capacity decay and cell failure of lithium-ion batteries (LIBs). Polymer binder provides the key function for a good interface property and for maintaining the electrode integrity of LIBs. Triethylene glycol monomethyl ether (TEG) moieties were incorporated into polymethacrylic acid (PMAA) to different extents at the molecular level. Microscratch tests of the graphite electrodes based on these binders indicate that the electrode is more flexible with 5 or 10% TEG in the polymer binders. Crack generation is inhibited by the flexible TEG-containing binder, compared to that of the unmodified PMAA-based electrode, leading to the better cycling performance of the flexible electrode. With a 10% TEG moiety in the binder, the graphite half-cell reaches a reversible capacity of >270 mAh/g at the 1C rate, compared to a value of ∼190 mAh/g for the unmodified PMAA binder.

Highly ordered AgInS₂-modified ZnO nanoarrays were fabricated via a low-cost hydrothermal chemical method, and their application as all-solid-state solar cells was also tested. A sensitizer and a buffer layer were developed around the surface of ZnO nanotubes in the preparation process, and this method is easily be manipulated to produce uniform structure. In this structure, the ZnO served as direct electron transport path, the ZnS as the buffer layer, and the ternary sensitizer AgInS₂ as absorber and outer shell. The novel all-solid-state hybrid solar cells (ITO/ZnO/ZnS/AgInS₂/P3HT/Pt) showed improved short-circuit current density (J_sc) of 7.5 mA/cm², open-circuit voltage (V_oc) of 512 mV, giving rise to a power conversion efficiency of 2.11%, which is the relatively highest value ever reported for ZnO-based all-solid-state hybrid solar cells. This better result is attributed to the improved absorption spectrum, high speed of photoinduced charge transmission velocity, and appropriate gradient energy gap structure, which implies a promising application in all-solid-state solar cells.

We report the preparation and characterization of monoolein cubosomes that can be easily surface modified through adsorption of a single layer of cationic poly-ε-lysine. Poly-ε-lysine coated cubosomes show remarkable stability in serum solution, are nontoxic and, are readily internalized by HeLa cells. The poly-ε-lysine coating provides chemical handles for further bioconjugation of the cubosome surface. We also demonstrate that the initial release rate of a hydrophilic drug, Naproxen sodium, from the cubosomes is retarded with just a single layer of polymer. Interestingly, cubosomes loaded with Naproxen sodium, recently shown to have anticancer properties, cause more apoptosis in HeLa cells when compared to free unencapsulated drug.

The effects of bioactive properties and surface topography of biomaterials on the adhesion and spreading properties of mouse preosteoblast MC3T3-E1 cells was investigated by preparation of different surfaces. Poly lactic-co-glycolic acid (PLGA) electrospun fibers (ES) were produced as a porous rough surface. In our study, coverslips were used as a substrate for the immobilization of 3,4-dihydroxyphenylalanine (DOPA) and collagen type I (COL I) in the preparation of bioactive surfaces. In addition, COL I was immobilized onto porous electrospun fibers surfaces (E-COL) to investigate the combined effects of bioactive molecules and topography. Untreated coverslips were used as controls. Early adhesion and growth behavior of MC3T3-E1 cells cultured on the different surfaces were studied at 6, 12, and 24 h. Evaluation of cell adhesion and morphological changes showed that the all the surfaces were favorable for promoting the adhesion and spreading of cells. CCK-8 assays and flow cytometry revealed that both topography and bioactive properties were favorable for cell growth. Analysis of β1, α1, α2, α5, α10 and α11 integrin expression levels by immunofluorescence, real-time RT-PCR, and Western blot and indicated that surface topography plays an important role in the early stage of cell adhesion. However, the influence of topography and bioactive properties of surfaces on integrins is variable. Compared with any of the topographic or bioactive properties in isolation, the combined effect of both types of properties provided an advantage for the growth and spreading of MC3T3-E1 cells. This study provides a new insight into the functions and effects of topographic and bioactive modifications of surfaces at the interface between cells and biomaterials for tissue engineering.

In the present study, a superhydrophobic polyurethane (PU) sponge with hierarchically structured surface, which exhibits excellent performance in absorbing oils/organic solvents, was fabricated for the first time through mussel-inspired one-step copolymerization approach. Specifically, dopamine (a small molecular bioadhesive) and n-dodecylthiol were copolymerized in an alkaline aqueous solution to generate polydopamine (PDA) nanoaggregates with n-dodecylthiol motifs on the surface of the PU sponge skeletons. Then, the superhydrophobic sponge that comprised a hierarchical structured surface similar to the chemical/topological structures of lotus leaf was fabricated. The topological structures, surface wettability, and mechanical property of the sponge were characterized by scanning electron microscopy, contact angle experiments, and compression test. Just as a result of the highly porous structure, superhydrophobic property and strong mechanical stability, this sponge exhibited desirable absorption capability of oils/organic solvents (weight gains ranging from 2494% to 8670%), suggesting a promising sorbents for the removal of oily pollutants from water. Furthermore, thanks to the nonutilization of the complicated processes or sophisticated equipment, the fabrication of the superhydrophobic sponge seemed to be quite easy to scale up. All these merits make the sponge a competitive candidate when compared to the conventional absorbents, for example, nonwoven polypropylene fabric.

Highly fluorescent surface modified polyacrylonitrile nanoparticles (PAN NPs) of 50 nm diameter were fabricated for selective Cu²⁺ sensing. After surface modification, the PAN NPs were converted to amidine/Schiff base dual-modified PAN nanoparticles (tPAN NPs) with a Cu²⁺ sensing property and high QY (0.19). The selectivity of tPAN NPs for Cu²⁺ is much higher than that of other metal ions due to the fact that amidine group on the surface of tPAN NPs has a higher binding affinity with Cu²⁺. The effect of other metal ions on the fluorescence intensity of the tPAN NPs was also studied, and other metal ions showed a low interference response in the detection of Cu²⁺. Furthermore, as a metal ion chelator, ethylenediaminetetraacetate can competitively interact with Cu²⁺ to recover the quenched fluorescence of tPAN NPs. The tPAN NPs are easily introduced into cells and exhibit low toxicity, enabling their use as a fluorescence sensor for Cu²⁺ in living cells. The tPAN NPs provide a new direction for the development of copper ion sensors in living cells.

To inhibit the metal catalytic coking and improve the oxidation resistance of TiN coating, rutile TiO₂ coating has been directly designed as an efficient anticoking coating for n-hexane pyrolysis. TiO₂ coatings were prepared on the inner surface of SS304 tubes by a thermal CVD method under varied temperatures from 650 to 900 °C. The rutile TiO₂ coating was obtained by annealing the as-deposited TiO₂ coating, which is an alternative route for the deposition of rutile TiO₂ coating. The morphology, elemental and phase composition of TiO₂ coatings were characterized by SEM, EDX and XRD, respectively. The results show that deposition temperature of TiO₂ coatings has a strong effect on the morphology and thickness of as-deposited TiO₂ coatings. Fe, Cr and Ni at.% of the substrate gradually changes to 0 when the temperature is increased to 800 °C. The thickness of TiO₂ coating is more than 6 μm and uniform by metalloscopy, and the films have a nonstoichiometric composition of Ti₃O₈ when the deposition temperature is above 800 °C. The anticoking tests show that the TiO₂ coating at a deposition temperature of 800 °C is sufficiently thick to cover the cracks and gaps on the surface of blank substrate and cut off the catalytic coke growth effect of the metal substrate. The anticoking ratio of TiO₂ coating corresponding to each 5 cm segments is above 65% and the average anticoking ratio of TiO₂ coating is up to 76%. Thus, the TiO₂ coating can provide a very good protective layer to prevent the substrate from severe coking efficiently.

Porous scaffolds consisting of bioactive inorganic nanoparticles and biodegradable polymers have gained much interest in bone tissue engineering. We report here a facile approach to fabricating poly(l-lactic acid)-grafted hydroxyapatite (g-HAp)/poly(lactide-co-glycolide) (PLGA) nanocomposite (NC) porous scaffolds by solvent evaporation of Pickering high internal phase emulsion (HIPE) templates, where g-HAp nanoparticles act as particulate stabilizers. The resultant porous scaffolds exhibit an open and rough pore structure. The pore structure and mechanical properties of the scaffolds can be tuned readily by varying the g-HAp nanoparticle concentration and internal phase volume fraction of the emulsion templates. With increasing the g-HAp concentration or decreasing the internal phase volume fraction, the pore size and the porosity decrease, while the Young’s modulus and the compressive stress enhance. Moreover, the in vitro mineralization tests show that the bioactivity of the scaffolds increases with increasing the g-HAp concentration. Furthermore, the anti-inflammatory drug ibuprofen (IBU) is loaded into the scaffolds, and the drug release studies indicate that the loaded-IBU exhibits a sustained release profile. Finally, in vitro cell culture assays prove that the scaffolds are biocompatible because of supporting adhesion, spreading, and proliferation of mouse bone mesenchymal stem cells. All the results indicate that the solvent evaporation based on Pickering HIPE templates is a promising alternative method to fabricate NC porous scaffolds for potential bone tissue engineering applications.