Stem cell engineering has enormous potential to study developmental processes and disease progression and provide new therapeutics. However, utilization of stem cells in regenerative medicine critically relies upon our understanding of how cells sense and respond to their extracellular environment. Cell-matrix interactions are fundamental to multiple processes such as cell migration, proliferation, cytoskeletal organization, lineage specificity, and morphogenesis. The matrix interfacial properties, in particular, plays a crucial role in modulating cell-matrix and cell-cell adhesion; however there does not currently exist a strategy to dissect the role of specific interfacial properties keeping the remaining matrix properties unchanged. In this talk I will describe the development of a tunable synthetic matrix to investigate the effect of interfacial hydrophobicity on various cellular functions. These novel matrices allow us to control the interfacial hydrophobicity in a systematic manner without altering other properties of the matrix such as their chemical and mechanical properties. We achieve this by copolymerizing acrylamide (Am) monomers with comonomers of varying hydrophobicity. Surprisingly, incorporation of a small amount of hydrophobic comonomers alters the “stickiness” of Am substrates, which are inherently known to be “non-sticky”. Our initial studies involving human mesenchymal stem cells (hMSCs) demonstrate that the adhesion of cells exhibit a nonmonotonic dependence with the matrix hydrophobicity. Concomitantly, there is also a marked change in cell morphology, spreading, and differentiation efficiency. Our studies also show that synthetic matrices with optimal interfacial properties support ex vivo expansion of mature cells (chondrocytes) and human pluripotent stem cells (embryonic stem cells and induced pluripotent stem cells).