| dc.description.abstract | Stem cells purified from human adipose tissue (hADSCs) via serial culture of stromal vascular fraction (SVF) on tissue culture plates show multilineage differentiation ability in vitro. In the past decades, extracellular matrices (ECMs) such as collagen, fibronectin, vitronectin, and laminin were used as coating or self-standing materials on 2D culture and 3D culture of stem cells, and the differentiation and proliferation ability of stem cells (e.g., ADSCs or bone marrow-derived mesenchymal stem cells) were investigated. However, the origin of these ECMs are mainly animal-derived or human recombinant, and, therefore, it is not suitable to use them for clinical applications due to xeno-origin contamination and high cost of ECMs. On the other hand, it has been shown that physical environmental factors, such as matrix elasticity, and small functional groups including oligopeptides can have significant effect in determining stem cell fate. To achieve our ultimate goal of affordable, personalized regenerative medicine, clinically safe and economical ways to proliferate stem cells are absolutely essential while maintaining their pluripotency as well as directing stem cell lineage specification without the use of induction chemicals.
Here I investigated pluripotency and differentiation ability of hADSCs cultured on poly(vinylalcohol-co-itaconic acid), PVA-IA, hydrogels grafted with several ECMs (collagen type I, Fibronectin, and oligo-vitronectin [VN]). The stiffness of PVA-IA hydrogels can be controlled by the crosslinking time from 6 hr to 48 hr in glutaraldehyde solution, which generates the elasticity from a 2.2 kPa to 3.7 kPa storage modulus corresponding 6.6 kPa to 11.1 kPa elastic modulus from calculation of E=3G’ [Biomaterials 29 (2008) 2757].
Primary hADSCs were found to maintain their pluripotency on relatively soft hydrogels grafted with Fibronectin and oligopeptide derived from Vitronectin (KGGPQVTRGDVFTMP) from pluripotent gene expression (Nanog, Sox2, Oct4, and klf4) but not on TCPS. From the immunostaining data showed that hADSCs on ECM-grafted PVA-IA films have higher expression of pluripotent proteins than those on TCPS in expansion medium. In the osteogenic differentiation analysis, hADSCs on TCPS have higher differentiation ratio than those on ECM-grafted PVA-IA films after 21 days culture in ostogenic medium.
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