Sulfonated chitosan and phosphorylated chitosan coated polylactide membrane by polydopamine-assisting for the growth and osteogenic differentiation of MC3T3-E1s

In this study, a poly(d,l-lactide) (PDLLA) membrane was prepared by the solution casting method, then the surface of the membrane was modified by polydopamine (PDOPA) as a substrate, followed by adsorption of different chitosan derivative sulfonated chitosan (SCS) or/and phosphorylated chitosan (PCS) to obtain different functionalized membranes, and two kinds of chitosan derivatives characterized by FTIR, elemental analysis and zeta potential. And different membranes were evaluated through surface potential, hydrophilicity, surface morphology and chemical compositions. In vitro, the cell culture results showed that the membrane functionalized by chitosan derivative could promote the proliferation of MC3T3-E1s and enhance the osteogenic differentiation by up-regulating the expression level of osteogenic genes compared to the PDLLA and P1/PDOPA membranes. Especially, when the outermost layer was SCS, the effect of promoting cell proliferation was better than that of PCS. However, for osteogenic differentiation, PCS had better quantitative experimental results than SCS. Therefore, SCS has superiority in promoting proliferation than PCS, but PCS is opposite in promoting osteogenic differentiation for MC3T3-E1s. The results suggested that PCS and SCS have the potential value to be used as a functional modified materials applied in bone tissue engineering.