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The development of wound dressings with combined antibacterial activities and pro-healing functions has always been an intractable medical task for treating bacterial wound infection. Herein, a novel injectable hybrid hydrogel dressing is developed, which is doped with nitric oxide (NO) donor (N,N'-di-sec-butyl-N,N'-dinitroso-1,4-phenylenediamine, BNN6) loaded two-dimensional polydopamine nanosheets (PDA NS). The hydrogel matrix is in situ formed through dynamic Schiff base crosslinking between hydrazide-modified 𝜸-polyglutamic acid (𝜸-PGA-ADH) and aldehyde-terminated Pluronic F127 (F127-CHO). Under 808 nm irradiation, the embedded PDA NS exhibits outstanding photothermal transform properties (56.1%) and on-demand NO release. The combination of photothermal and NO gas therapy with a synergistic antibacterial effect works on both Escherichia coli and Staphylococcus aureus in vitro. Furthermore, a full-thickness skin defect model also demonstrates that the hybrid hydrogel shows outstanding antibacterial properties and effectively accelerates the wound healing process. Overall, this study provides a facile and promising method for the fabrication of PDA NS based multifunctional hydrogel dressing for the application of infectious skin wound healing.

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A novel amphiphilic graft copolymer consisting of hydrophilic poly(acrylic acid) backbones and hydrophobic poly(butyl methacrylate) side chains was synthesized by successive atom transfer radical polymerization followed by hydrolysis of poly‐(methoxymethyl acrylate) backbone. A grafting‐from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distributions (polydispersity index < 1.40). Hydrophobic side chains were connected to the backbone through stable CC bonds instead of ester connections. Poly(methoxymethyl acrylate) backbone was easily hydrolyzed to poly(acrylic acid) backbone with HCl without affecting the hydrophobic side chains. The amphiphilic graft copolymer could form stable micelles in water. The critical micelle concentration in water was determined by a fluorescence probe technique. The morphology of the micelles was preliminarily explored with transmission electron microscopy and was found to be spheres. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6857–6868, 2006

A novel perfluorocyclobutyl aromatic ether-based ABA triblock copolymer (A: polystyrene block; B: perfluorocyclobutyl aromatic ether-based fluoropolymer block) was synthesized by combination of atom transfer radical polymerization (ATRP) of styrene and thermal step-growth cycloaddition polymerization of trifluorovinyl monomer. We first synthesized a new ATRP initiator containing the trifluorovinyl group, which can initiate ATRP of styrene in a controlled way to obtain well-defined polystyrene with narrow molecular weight distribution (Mw/Mn < 1.10). The apparent polymerization rate exhibited first-order relation with respect to the concentration of monomer and the molecular weight increases linearly with the conversion of monomer. Second, fluoropolymer containing a perfluorocyclobutyl aromatic ether unit was prepared by solution polymerization and followed by reacting with ATRP initiator containing a trifluorovinyl group to get ATRP macroinitiator with two initiation groups at both ends. The macroinitiator-initiated ATRP of styrene to obtain ABA triblock copolymer. The copolymer shows excellent solubility in conventional solvents.

Gibberellin 2-oxidase (GA 2-oxidase) plays very important roles in plant growth and development. In this study, the AtGA2ox8 gene, derived from Arabidopsis (Arabidopsis thaliana), was transformed and over-expressed in rapeseed (Brassica napus L.) to assess the role of AtGA2ox8 in biomass accumulation and lignification in plants. The transgenic plants, identified by resistant selection, polymerase chain reaction (PCR) and reverse-transcription PCR (RT-PCR) analyses, and green fluorescence examination, showed growth retardation, flowering delay, and dwarf stature. The fresh weight and dry weight in transgenic lines were about 21% and 29% lower than those in wild type (WT), respectively, and the fresh to dry weight ratios were higher than that of WT. Quantitative measurements demonstrated that the lignin content in transgenic lines decreased by 10%-20%, and histochemical staining results also showed reduced lignification in transgenic lines. Quantitative real-time PCR analysis indicated that the transcript levels of lignin biosynthetic genes in transgenic lines were markedly decreased and were consistent with the reduced lignification. These results suggest that the reduced biomass accumulation and lignification in the AtGA2ox8 over-expression rapeseed might be due to altered lignin biosynthetic gene expression.

Human respiratory syncytial virus (RSV), a major cause of severe respiratory diseases, constitutes an important risk factor for the development of subsequent asthma. In searching for its mechanism, the present study was designed to screen the interacting proteins of two important nonstructural (NS) proteins in human BECs. The subcellular localization and the effects of NS on HOX gene expression were also examined. The results showed that NS1 was distributed throughout the nucleus and cytoplasm, while NS2 was mainly distributed in cytoplasm of BECs. NS1 interacted specifically with host histone H2BD, inducing histone ubiquitination and subsequent HOX gene expression. In conclusion, the results of the present study indicated that RSV NS-1 induces HOX gene expression, through histone ubiquitination in a BEC cell line, which may provide a novel conception for understanding the relationship between severe RSV bronchiolitis during early life and the development of subsequent asthma.

Special rutile titanium dioxide (TiO 2) hollow microspheres were prepared successfully through hydrothermal methods when tetrabutyl titanate was adopted as raw material, β-cyclodextrin as template agent and polyvinylpyrrolidone as auxiliary agent. The effect of the concentration of hydrochloric acid and the temperature on the formation of TiO 2 morphology was discussed and the structure of the powders confirmed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscope. The colour of products changed from black to white after roasted, and the results of FT-IR and XRD measures showed its structure conforming to the rutile TiO 2. It was found that the TiO 2 powders were hollow microspheres, and its surface tightly wrapped by nanorods for uniform, smooth, and orientation rule, which was of larger specific surface area.