No abstract

Delayed wound healing has a profound impact on patients, healthcare, and society. Platelet‐rich plasma (PRP) gel, as a preparation for regenerative medicine, has proven to be of clinical value in various wound treatments. Nevertheless, its weak mechanical properties and consequent burst release effect have restricted its application and efficacy. Here, an engineered PRP dual‐network hydrogel (named DN gel) based on sodium alginate is constructed through a simple “one‐step” activation process. Its improved gelling property and sustained release of growth factors may be beneficial for clinical use. Evaluations in rats indicate that DN gel promote wound healing in terms of rapid re‐epithelialization, up‐regulated growth factor levels and early transitions in the wound healing and angiogenesis stages. As a proof of concept, DN gel also exhibits superior healing efficiency in a porcine wound model. These results demonstrate the great potential of transforming this hydrogel into the next generation of PRP‐based bioactive wound dressing.

Catheter-related infection is a great challenge to modern medicine, which causes significant economic burden and increases patient morbidity. Hence, there is a great requirement for functionalized surfaces with inherently antibacterial properties and biocompatibility that prevent bacterial colonization and attachment of blood cells. Herein, we developed a strategy for constructing polymer brushes with hierarchical architecture on polyurethane (PU) via surface-initiated atom-transfer radical polymerization (SI-ATRP). Surface-functionalized PU (PU-DMH) was readily prepared, which comprised of poly­(3-[dimethyl-[2-(2-methylprop-2-enoyloxy)­ethyl]­azaniumyl]­propane-1-sulfonate) (PDMAPS) brushes as the lower layer and antimicrobial peptide-conjugated poly­(methacrylic acid) (PMAA) brushes as the upper layer. The PU-DMH surface showed excellent bactericidal property against both Gram-positive and Gram-negative bacteria and could prevent accumulation of bacterial debris on surfaces. Simultaneously, the PU-DMH samples possessed good hemocompatibility and low cytotoxicity. Furthermore, the integrated antifouling and bactericidal properties of PU-DMH under hydrodynamic conditions were confirmed by an in vitro circulating model. The functionalized surface possessed persistent antifouling and bactericidal performances both under static and hydrodynamic conditions. The microbiological and histological results of animal experiments also verified the in vivo anti-infection performance. The present work might find promising clinical applications for preventing catheter-related infection.

Novel nitric oxide (NO) responsive monomers (NAPMA and APUEMA) containing o-phenylenediamine functional groups have been polymerized to form NO-responsive macromolecular chains as truly biomimetic polymers. Upon exposure to NO--a ubiquitous cellular signaling molecule--the NAPMA- and APUEMA-labeled thermoresponsive copolymers exhibited substantial changes in solubility, clearly characterized by tuneable LCST behavior, thereby inducing self-assembly into nanoparticulate structures. Moreover, the NO-triggered self-assembly process in combination with environmentally sensitive fluorescence dyes could be employed to detect and image endogenous NO.

Ternary blend films were prepared with different ratios of starch/polyvinyl alcohol (PVA)/citric acid. The films were characterized by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis, as well as Fourier transform infrared (FTIR) analysis. The influence of different ratios of starch/polyvinyl alcohol (PVA)/citric acid and different drying times on the performance properties, transparency, tensile strength (TS), water vapor permeability (WVP), water solubility (WS), color difference (∆E), and antimicrobial activity of the ternary blends films were investigated. The starch/polyvinyl alcohol/citric acid (S/P/C 1:1:0 , S/P/C 3:1:0.08 , and S/P/C 3:3:0.08 ) films were all highly transparent. The S/P/C 3:3:0.08 had a 54.31 times water-holding capacity of its own weight and its mechanical tensile strength was 46.45 MPa. In addition, its surface had good uniformity and compactness. The S/P/C 3:1:0.08 and S/P/C 3:3:0.08 showed strong antimicrobial activity to Listeria monocytogenes and Escherichia coli, which were the food-borne pathogenic bacteria used. The freshness test results of fresh figs showed that all of the blends prevented the formation of condensed water on the surface of the film, and the S/P/C 3:1:0.08 and S/P/C 3:3:0.08 prevented the deterioration of figs during storage. The films can be used as an active food packaging system due to their strong antibacterial effect.