Ag nanosheets grown on Cu nanowire-based flexible films for sensitive non-enzymatic glucose sensors.

Cu nanowire (Cu NW) and Ag nanosheet (Ag NS) bimetallic nanocomposites were fabricated on a flexible polyethylene terephthalate (PET) slice for non-enzymatic glucose sensing via a facile two-step approach, vacuum filtration, and galvanic displacement. Low-cost Cu NW-based conductive films were employed as the conductive substrates to substitute the traditional glassy carbon electrodes or indium tin oxide electrodes. The highly stable Ag NSs grow directly on the surface of Cu NWs without additional binders. The AgNO3 concentration and displacement time were adjusted to control the consumption of Cu NWs and the growth of Ag nanostructures. With the large load of Ag and the great connection of Cu NWs, a high sensitivity of 2033 µA mM-1cm-2, a fast amperometric response of 2 s, a wide linear range of 0.0015-4.02 mM, and a satisfactory result in human serum analysis were obtained by this novel Ag NS/Cu NW/PET sensor. Especially the sensitivity of the sensor was over four-fold higher than that of pure Cu NWs/PET, benefiting from the synergistic effect of bimetals. Furthermore, the Ag NS/Cu NW/PET sensor demonstrated a stable amperometric signal against mechanical bending. The material holds promise to use to fabricate flexible electrochemical devices.

Spermidine-Functionalized Injectable Hydrogel Reduces Inflammation and Enhances Healing of Acute and Diabetic Wounds In Situ.

The inflammatory response is a key factor affecting tissue regeneration. Inspired by the immunomodulatory role of spermidine, an injectable double network hydrogel functionalized with spermidine (DN-SPD) is developed, where the first and second networks are formed by dynamic imine bonds and non-dynamic photo-crosslinked bonds respectively. The single network hydrogel before photo-crosslinking exhibits excellent injectability and thus can be printed and photo-crosslinked in situ to form double network hydrogels. DN-SPD hydrogel has demonstrated desirable mechanical properties and tissue adhesion. More importantly, an "operando" comparison of hydrogels loaded with spermidine or diethylenetriamine (DETA), a sham molecule resembling spermidine, has shown similar physical properties, but quite different biological functions. Specifically, the outcomes of 3 sets of in vivo animal experiments demonstrate that DN-SPD hydrogel can not only reduce inflammation caused by implanted exogenous biomaterials and reactive oxygen species but also promote the polarization of macrophages toward regenerative M2 phenotype, in comparison with DN-DETA hydrogel. Moreover, the immunoregulation by spermidine can also translate into faster and more natural healing of both acute wounds and diabetic wounds. Hence, the local administration of spermidine affords a simple but elegant approach to attenuate foreign body reactions induced by exogenous biomaterials to treat chronic refractory wounds.

Preparation and in vitro study of hydrochloric norvancomycin encapsulated poly (d,l-lactide-co-glycolide, PLGA) microspheres for potential use in osteomyelitis.

HNV-loaded PLGA microspheres (HNV-PLGA MSs) were prepared by water-in-oil-in-water (w/o/w) double emulsion solvent evaporation technique. The surface of prepared HNV-PLGA MSs is smooth and nonporous with an average diameter of 69.9 µm. The drug-loading rate and encapsulation rate of HNV-PLGA MSs are 4.40 ± 0.26% and 48.51 ± 14.83%, respectively. Additionally, 43.36% of HNV was released from PLGA MSs after seven days of incubation. The antibacterial effects of HNV released from PLGA were as good as the pure HNV. HNV-loaded PLGA microspheres were successfully prepared using double emulsion solvent evaporation technique and their properties met the requirements for local anti-infection.