We report a biomimetic mineralization of hydroxyapatite induced by poly-dopamine-functionalized reduced graphene oxide (RGO-PDA). Graphene oxide was first simultaneously reduced and surface functionalized by one-step oxidative polymerization of dopamine. The resultant RGO-PDA was further used as a bioinspired surface to mimic the mineralization of hydroxyapatite during bone formation. MC3T3-E1 cells were cultured on the RGO-PDA substrates to observe various cellular activities and hydroxyapatite mineralization. The MC3T3-E1 cells on RGO-PDA substrates show higher cellular activities such as proliferation, adhesion, and osteogenic differentiation over the bare glass and graphene oxide substrates. Those results suggest the potentials of using RGO-PDA as osteogenesis-promoting scaffolds for successful applications in bone tissue regeneration.

In the present study, a novel polysaccharide, APS2-1, was isolated and purified from Astragalus membranaceus using DEAE-cellulose and Sephadex G-100 chromatography. The effect of APS2-1 on the promotion of wound healing was evaluated and its preliminary mechanism was investigated. In vitro experiments showed that APS2-1 was able to promote human skin fibroblast (HSF) propagation and accelerate cell cycle progression. For further examination, a scalded mice model was used to verify the effect of APS2-1 and investigate its mechanism of action. The analysis of biochemical parameters, including cyclin D1, inhibitor of nuclear factor κBα (IκBα), transforming growth factor (TGF)-β1, basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) showed that APS2-1 inhibited the increase in cyclin D1 and IκBα, and promoted the expression of TGF-β1, bFGF and EGF, which was further confirmed by histopathological observation. These results suggested that APS2-1 possessed high potential in wound healing and its mechanism was associated with inhibiting inflammation, accelerating cell cycle and promoting the secretion of repair factors.