Traction stresses and motility of fibroblasts are different on RGD- and fibronectin-modified elastic substrata

We report here our findings of traction stresses and motility of fibroblasts cultured on polyacrylamide substrata modified covalently with RGD (Arg-Gly-Asp) and fibronectin. Although projected cell areas are similar, we observe that the traction stresses are significantly different-nearly ten-fold higher on fibronectin-modified substrata compared to RGD-modified substrata. Immunofluorescence reveals differences in organization of actin stress fibers that correlate with observed differences in traction. A biphasic relationship between cell speed and fibronectin concentration is observed, but on RGD-modified substrata, cell speed increases with RGD concentration until it reaches a plateau. Our findings have implications on the use of RGD-modified biomaterials on cellular response.