pH and glucose dual-responsive injectable hydrogels were prepared through the cross-linking of Schiff's base and phenylboronate ester using phenylboronic-modified chitosan, poly(vinyl alcohol) and benzaldehyde-capped poly(ethylene glycol). Protein drugs and live cells could be incorporated into the hydrogels during the in situ cross-linking, displaying sustained and pH/glucose-triggered drug release from the hydrogels and cell viability and proliferation in the three-dimensional hydrogel matrix as well. Hence, the hydrogels with insulin and fibroblasts were considered as bioactive dressings for diabetic wound healing. A streptozotocin-induced diabetic rat model was used to evaluate the efficacy of hydrogel dressings in wound repair. The results revealed that the incorporation of insulin and L929 in the hydrogels could promote neovascularization and collagen deposition and enhance the wound-healing process of diabetic wounds. Thus, the drug- and cell-loaded hydrogels have promising potential in wound healing as a medicated system for various therapeutic proteins and live cells.

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Nano-structured molybdenum disulfide (MoS2) catalysts have been extensively developed for the hydrogen evolution reaction (HER). Herein, a novel hydrothermal intercalation approach is employed to fabricate nanoflower-like 2H-MoS2 with the incorporation of three polymers, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and polyethylenimine (PEI). The as-prepared MoS2 specimens were characterized by techniques of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), together with Raman and Fourier transform infrared spectroscopy (FTIR). The HER properties of these lamellar nanoflower-like composites were evaluated using electrochemical tests of linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The existent polymer enlarges the interlayer spacing of the lamellar MoS2, and reduces its stacked thickness. The lamellar MoS2 samples exhibit a promoting activity in HER at low additions of these three polymers (0.04 g/g MoS2 for PVA and PEI, and 0.08 g/g MoS2 for PVP). This can be attributed to the fact that the expanded interlayer of MoS2 can offer abundant exposed active sites for HER. Conversely, high additions of the polymers exert an obvious interference in the HER activity of the lamellar MoS2. Compared with the samples of MoS2/PVP-0.08 and MoS2/PEI-0.04, the MoS2/PVA-0.04 composite exhibits excellent activity in HER, in terms of higher current density and lower onset potential. OPEN ACCESSMetals 2015, 5 1830

A folate-conjugated and pH-sensitive micellar system co-encapsulating doxorubicin and paclitaxel was developed for targeted and combination chemotherapy.