Osteogenesis and mineralization of mesenchymal stem cells in collagen type I-based recombinant peptide scaffolds.

Recombinant peptides have the power to harness the inherent biocompatibility of natural macromolecules, while maintaining a defined chemistry for use in tissue engineering. Creating scaffolds from peptides requires stabilization via crosslinking, a process known to alter both mechanics and density of adhesion ligands. The chemistry and mechanics of linear scaffolds from a recombinant peptide based on human collagen type I (RCP) was investigated after crosslinking. Three treatments were compared: dehydrothermal treatment (DHT), hexamethylene diisocyanate (HMDIC), and genipin. With crosslinking, mechanical properties were not significantly altered, ranging from 1.9 to 2.7 kPa. However, the chemistry of the scaffolds was changed, affecting properties such as water uptake, and initial adhesion of human mesenchymal stem cells (hMSCs). Genipin crosslinking supported the lowest adhesion, especially during osteoblastic differentiation. While significantly altered, RCP scaffold chemistry did not affect osteoblastic differentiation of hMSCs. After four weeks in vitro, all scaffolds showed excellent cellular infiltration, with up-regulated osteogenic markers (RUNX2, Osteocalcin, Collagen type I) and mineralization, regardless of the crosslinker. Thus, it appears that, without significant changes to mechanical properties, crosslinking chemistry did not regulate hMSC differentiation on scaffolds from recombinant peptides, a growing class of materials with the ability to expand the horizons of regenerative medicine.