| The extracellular matrix (ECM) that surrounds cells is a self-assembled network of biomolecules that present cues to cell surface receptors to direct cell function. For example, ECM proteins interact with cell surface integrin receptors to mediate cell adhesion to the ECM. In turn, ECM protein-integrin binding initiates intracellular signaling cascades and directs cytoskeletal organization. Additionally, proteins and proteoglycans present throughout the ECM bind to growth factors, a class of soluble signaling molecules that direct cell function by binding to cognate cell surface receptors, to localize growth factor activity within distinct extracellular environments.;Traditionally, efforts aimed at understanding the role of ECM-derived biomolecules on cell function have relied on the following experimental approach: a biomolecule of interest is non-specifically adsorbed onto a cell culture substrate, such as tissue culture-treated polystyrene, cells are seeded onto the substrate, and the influence of the adsorbed biomolecule on cell function is studied. While such approaches have been successful, a detailed understanding of the influence of the biomolecule on cell function is hindered by limitations inherent to the non-specific adsorption process. In particular, the concentration of biomolecules in solution does not typically correlate with the density of biomolecules adsorbed on a substrate, and the orientation of adsorbed biomolecules is influenced by the surface chemistry of the underlying substrate. Together, these phenomena limit the understanding of the correlation between cell function and ECM epitope type or density that can be achieved.;The work presented herein describes the development of chemically well-defined cell culture substrates that directly limitations associated with traditional cell culture approaches. In particular, the work presented herein describes cell culture substrates that allow for covalent immobilization of peptides demonstrating specific, non-covalent interaction with cell surface receptors and ECM biomolecules. Importantly, the underlying substrate is resistant to non-specific protein adsorption and, as such, allows for direct comparison of the modulation of cell function by different peptides, or the same peptide at different surface densities. Throughout this work, these substrates will be used to characterize the influence of different extracellular cues on mesenchymal stem cell functions, such as adhesion, proliferation, and differentiation. |
