Abstract

Recruitment of endogenous mesenchymal stem cells (MSCs) has become an attractive strategy for in situ tissue regeneration. However, it is of great importance to endow an implant with a specific affinity to MSCs, for many types of cells such as immune cells and fibroblasts can also be recruited. It has been demonstrated that E7 peptides have a specific affinity to MSCs, but their selectivity for MSCs when co-cultured with other cells, especially in flow conditions, has rarely been investigated. In this study, E7-modified collagen substrates were prepared using sulfosuccinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (sulfo-SMCC) as the coupling agent. The results of X-ray photoelectron spectroscopy (XPS) and quartz crystal microbalance (QCM) proved that the densities of the immobilized E7 peptides could be modulated by changing the amounts of sulfo-SMCC. The results of cell adhesion rate, adhesion area and adhesion force demonstrated that the immobilization of E7 peptides led to a significant enhancement of the adhesion of bone marrow-derived MSCs (BMSCs) compared to RAW264.7 cells and NIH3T3 cells. The selective adhesion was verified by co-culturing BMSCs with RAW264.7 cells and NIH3T3 cells, which indicated that higher proportions of BMSCs were adhered on the E7-immobilized substrates. By mimicking in vivo flow circumstances, the selective capture of BMSCs by the E7-modified substrates was revealed by a flow model. All these results suggest that E7 immobilization might be a promising strategy for an implant to achieve a better regeneration outcome by enhancing the affinity to the recruited MSCs.