Nano-graphene oxide/polyurethane nanofibers: mechanically flexible and myogenic stimulating matrix for skeletal tissue engineering.

For skeletal muscle engineering, scaffolds that can stimulate myogenic differentiation of cells while possessing suitable mechanical properties (e.g. flexibility) are required. In particular, the elastic property of scaffolds is of importance which helps to resist and support the dynamic conditions of muscle tissue environment. Here, we developed highly flexible nanocomposite nanofibrous scaffolds made of polycarbonate diol and isosorbide-based polyurethane and hydrophilic nano-graphene oxide added at concentrations up to 8%. The nano-graphene oxide incorporation increased the hydrophilicity, elasticity, and stress relaxation capacity of the polyurethane-derived nanofibrous scaffolds. When cultured with C2C12 cells, the polyurethane-nano-graphene oxide nanofibers enhanced the initial adhesion and spreading of cells and further the proliferation. Furthermore, the polyurethane-nano-graphene oxide scaffolds significantly up-regulated the myogenic mRNA levels and myosin heavy chain expression. Of note, the cells on the flexible polyurethane-nano-graphene oxide nanofibrous scaffolds could be mechanically stretched to experience dynamic tensional force. Under the dynamic force condition, the cells expressed significantly higher myogenic differentiation markers at both gene and protein levels and exhibited more aligned myotubular formation. The currently developed polyurethane-nano-graphene oxide nanofibrous scaffolds, due to their nanofibrous morphology and high mechanical flexibility, along with the stimulating capacity for myogenic differentiation, are considered to be a potential matrix for future skeletal muscle engineering.