CytoSoft products provide a tool to culture cells on PDMS substrates with various rigidity covering a broad physiological range, including 0.2, 0.5, 2, 8, 16, 32, and 64 kPa. The CytoSoft Discovery Kit comes with a 6-well plate of each stiffness (7 plates in total), allowing you to test how your cells behave across a broad range of physiologically relevant stiffness. The thickness of the silicone gel is uniform with a ~0.5 mm thick layer of silicone in each dish that is fully compatible with mammalian cell cultures. The silicone gels are activated and ready to bind to a purified ECM, such as PureCol type I collagen (#5005) prior to cell addition. The plates are packaged individually and sterilized. The rigidity of the substrate to which cells adhere can have a profound effect on cell morphology and gene expression. CytoSoft products provide a tool to culture cells on substrates with various rigidities covering a broad physiological range.