Effect of RGD-modified silk material on the adhesion and proliferation of bone marrow-derived mesenchymal stem cells

In order to investigate the effect of Arg-Gly-Asp (RGD) peptide-modified silk biomaterial on the adhesion and proliferation of bone marrow-derived mesenchymal stem cells (MSCs), MSCs of third generation were seeded onto the surface of RGD-decorated silk (silk-RGD group), silk alone (silk group) or tissue culture plate (TCP group). After incubation for 4 or 12 h, MSCs were examined quantitatively by using precipitation method for cell attachment. The cell proliferation, which was defined as cell density, was compared among the three groups after culture for 1, 2, 3, and 4 days. Cell skeleton, which was labeled fluorescently, was observed under laser confocal microscope after 24 h of culture. The results showed that cell adhesion rate in silk-RGD group was higher than in silk group (P<0.05), but similar to that in TCP group after incubation for 4 or 12 h (P>0.05). There were no significant differences in the cell proliferation among the three groups at different time points (P>0.05 for all). Laser confocal microscopy revealed that in silk-RGD group, MSCs, strongly fluorescently stained, spread fully, with stress fibers clearly seen, while in silk group, actin filaments were sparsely aligned and less stress fibers were found. It was concluded that RGD peptide could improve the adhesion of MSCs to the silk scaffold, but had no impact on the proliferation of the cells.