| dc.description.abstract | Human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), are attractive source for regenerative tissue engineering. Typically, hPSCs are used to culture on animal feeder cells or secreted protein-coated dishes, such as mouse embryonic fibroblast (MEF) or Matrigel, respectively which secrete extracellular matrices (ECMs) and growth factors for cell attachment but provide uncertain chemical compositions for cell growth. On the other hand, reliable biomaterials such as xeno-free synthetic peptides-immobilized surface, offer not only a chemically defined composition but also reproducible conditions for hPSC cultivation.
In previous studies in our laboratory, hPSCs were cultured on polyvinyl alcohol-co-itaconic acid (PVA-IA) hydrogels, which were conjugated with oligo-vitronectin (KGGPQVTRGDVFTMP) stably. However, once I induced the hPSCs for further differentiation, hPSCs detached much easier comparing to hPSCs cultured on other ECM-coated surface. In this study, I designed new peptides from Laminin (LN), which was a remarkable ECM for cell differentiation in previous studies where the key cell binding mechanism was investigated by using PVA-IA hydrogels. Several new designs of laminin-derived peptide (PASYRGDSC and PMQKMRGDVFSP) were grafted on PVA-IA hydrogels, which provided RGD binding motifs and constituted the major recognition system for hPSC adhesion. These synthetic peptides were investigated by comparing the ability to support long term hPSCs cultivation and differentiation into mesenchymal stem cells (MSCs) and cardiomyocytes (CMs). The different lengths and sequences of joint segment, mimicking the original ECM, were evaluated to investigate the length effect and the effect of structures on hPSC culture and differentiation. Moreover, the C-terminus of peptides were treated with and without amide modification (-CONH2) to compare the efficiency of hPSC attachment. Furthermore, after hPSC cultivation on those synthetic peptides-grafted surface, hPSCs were evaluated for the expression level of four pluripotent protein (Oct4, Sox2, SSEA-4 and Nanog) expression. These results will help understanding of the cell-substrate binding mechanisms in sustaining hPSC culture and differentiation . | en_US |