Optimizing BMSC Adhesion on PD-Coated PDMS

PDMS substrates were prepared by mixing ten parts of silicone elastomer base with one part of curing agent (SYLGARD, Dow Corning, USA) and stirred. The mixture was then poured into well plates or culture dishes, degassed for 30 min in a vacuum oven to remove air bubbles, followed by heat-curing at 70 °C for 100 min. Surface modification was performed by immersing the native PDMS surface in dopamine solution (Sigma Aldrich, Singapore) prepared in 10 mM Tris-HCl (pH 8.5). PD concentration (0.000%w/v–0.100%w/v) and duration of coating (0–24 h) were varied to investigate the effect of these parameters on the stability of BMSC adhesion and proliferation. After PD coating, the surfaces were rinsed twice with 1X Phosphate Buffered Saline (PBS) to remove unattached PD molecules. Additional coating of 20 μg/ml collagen type 1 (Life Technologies, Singapore) was performed to evaluate the combinatorial effect of PD and collagen on BMSC behaviour. Lastly, the uncoated and PD-coated PDMS substrates were UV-sterilized for 1 h prior to cell culture.