Mechanical properties and osteogenic activity of poly(l-lactide) fibrous membrane synergistically enhanced by chitosan nanofibers and polydopamine layer

To synergistically improve the mechanical properties and osteogenic activity of electrospinning poly(l-lactide) (PLLA) membrane, chitosan (CS) nanofibers were firstly introduced to prepare sub-micro and nanofibers interpenetrated PLLA/CS membrane, which was further surface modified with a polydopamine (PDA) layer to obtain PLLA/CS-PDA. Surface morphology, porosity, surface area and hydrophilicity of the obtained fibrous membranes were studied in detail. As compared to pure PLLA, the significant increase in the mechanical properties of the PLLA/CS, and especially of the PLLA/CS-PDA, was confirmed by tensile testing both in dry and wet states. Cells culture results indicated that both the PLLA/CS and PLLA/CS-PDA membranes, especially the latter, were more beneficial to adhesion, spreading and proliferation, as well as up-regulating alkaline phosphate activity and calcium deposition of MC3T3-E1 cells than PLLA membrane. Results suggested there was a synergistic effect of the CS nanofibers and PDA layer on the mechanical properties and osteogenic activity of PLLA membrane.