Micropatterned Substrates for Cell Culture

Micropatterned substrates were made with standard soft lithography techniques to create a silicon master mold^{25 (link)}. PDMS was prepared by mixing Sylgard-184 elastomer and its accompanying curing agent (Dow Corning) in a 10:1 (w/w) ratio respectively. After degassing, the PDMS mixture was added over the master and cured overnight at 60 °C. Human fibronectin (Invitrogen) was added to stamps at a concentration of 40 µg ml⁻¹ for 1 h. Non-adsorbed fibronectin solution was removed by blow drying with air. To prepare the substrate, coverslips were spin-coated with a 9:1 PDMS:hexane solution at a speed of 5000 rpm for 2 min and left to set overnight at room temperature. The coverslips were treated with UV-ozone immediately before placing the stamps in contact with the coated coverslip by briefly applying uniform pressure and then passivated with 0.1% Pluronic F-127 (Sigma–Aldrich) for 1 h. Stamped substrates were stored at 4 °C in 1× PBS for up to one week.