Tuning physio-mechanical properties of graded micropillar polydimethylsiloxane substrates for cellular attachment and guided migration

The study of cell-substrate interaction and cellular behavior is critical in tissue engineering and microfluidic research. Since the substrate properties affect the cellular response, it is essential to tune the properties of the polymeric substrate to mimic the native microenvironment for cells. Due to its tunable physical and mechanical properties, polydimethylsiloxane (PDMS) is widely used to study cellular mechanics. This study focused on investigating the effects of substrate stiffness and wettability of PDMS micropillar substrates on cellular response. Mixing different base-to-curing agent ratios of PDMS resulted in different stiffness, while the corona discharge increased the surface wettability. By culturing 3T3 fibroblast cells, it was found that cells preferred a stiffer and more hydrophilic substrate (5:1) compared to the softer and less hydrophilic substrate (20:1) for long-term cell adhesion and migration. This study proves that biomaterials with appropriate stiffness should be chosen to study the cell mechanobiology of this cell line.