We proposed to develop novel, well-defined, synthetic extracellular matrices that support survival and proliferation of human embryonic stem cells. This is an important, unmet need in the field and development of such a substrate would aid in moving stem cell therapies to the clinic. In the first year of support, we have made significant progress. First, we characterized the cell surface receptors for matrix proteins on stem cells and identified specific proteins that will support adhesion and growth of the cells. Second, using an interdisciplinary approach, we developed a novel method to screen peptides from these proteins for their ability to support adhesion and proliferation of the stem cells. Finally, we identified a cyclic RGD peptide that supports growth of human embryonic stem cells. We are continuing to screen for new peptides that might be combined with cyclic RGD to optimize a scalable, inexpensive, clinically compliant substrate.