(596a) Engineering Cell-Material Interfaces for Long-Term Expansion of Human Pluripotent Stem Cells

Developing cost-effective, and scalable synthetic matrices for long-term expansion of human pluripotent stem cells (hPSCs) is important to realize their applications, ranging from drug screening platforms to regenerative medicine. Here, we report the development of a synthetic matrix containing heparin mimetic moieties to support long-term expansion of hPSCs (>20 passages) in a chemically defined Stempro medium. HPSCs expanded on these hydrogels maintained their characteristic morphology, colony forming ability, karyotypic stability, and differentiation potential. The synthetic matrix-expanded hPSCs exhibited pluripotent markers comparable to those cultured on Matrigel. Employing the hydrogel-based synthetic platform, we also investigated the effect of various physicochemical properties of the matrix (e.g., functional group, hydrophobicity, and matrix rigidity) on adhesion, growth, and self-renewal of hPSCs. Our findings suggest that the synthetic hydrogels having an optimal interfacial hydrophobicity (or hydrophilicity) and matrix rigidity support long-term self-renewal of hPSCs. The observed cellular responses are explained in terms of matrix mediated binding of extracellular matrix proteins and growth factors, which provide a conducive microenvironment for the initial adhesion and growth of hPSCs. Such a matrix-assisted initial instructive environment would then be harnessed by the cells to activate the necessary integrin profile as well as ECM synthesis to create a niche that support self-renewal in contrast to differentiation. The synthetic matrices comprising of “off-the shelf” components are easy to synthesize and do not require any sophisticated processing thus making them cost-effective and translational.  Furthermore, synthetic matrices with defined bulk and interfacial properties will be an ideal tool to understand the molecular mechanisms that control fate and commitment of hPSCs.