(601af) Role of ECM Mimicking Biophysical Cues and Biochemical Cues on Directed Migration of 3T3 Fibroblasts

To understand the role cell migration plays in complex biological processes such as cancer metastasis and wound healing, it is important to study the motility of cells in their native environment. Many cell motility studies are performed in presence of biochemical gradient using a process known as chemotaxis, which often overlook the phenomena involving mechanical stressors. To understand the role of both biophysical and biochemical cues, in this study, NIH-3T3 mouse fibroblast cells are subjected ECM mimicking nanofibers (biophysical cue) within a flow-based microfluidic device with a spatially variant but temporally invariant biochemical gradient (biochemical cue). The microfluidic device was fabricated with PDMS using standard soft lithography techniques in which four different types of surfaces were tested: 1) glass substrate, 2) Polystyrene (PS) substrate, 3) PS nanofibers on the PS substrate, and 4) suspended PS nanofibers. The 300 nm polystyrene nanofibers were fabricated using STEP method developed by Nain et al. Inside the device, the nanofibers are placed perpendicular to the flow and parallel to the direction of the chemical gradient. Our preliminary result indicates that the cells on suspended fibrous scaffolds are affected both by the chemical gradient and the mechanical gradient due to the different structural stiffness along the fibers. While the cells on glass, PS, and PS nanofibers on PS substrate showed high chemotactic index, the cells on suspended fibers showed no preference towards higher chemotactic concentrations. The durotactic gradient presented by fibers allows the cells to travel in the opposite direction as the chemical gradient. In future studies, experiments with nanofibers perpendicular to the chemical gradient will be conducted to further investigate the relative importance of biophysical and biochemical cues on cell migration.