735 Control of Cell Morphology and Measurement of Traction Forces of Smooth Muscle Cells Using Microfabricated Devices

Although cellular traction forces are believed to play an important role in the interactions between cells and their substrates, little is known of the effect of mechanical environment on the magnitude and direction of traction forces and hence how intracellular structures contribute to traction forces. In this study, microfabricated substrates, array of micropillars with different spacing, were used to estimate cellular traction forces of smooth muscle cells, particularly exploring the contribution of microtubules to traction forces. A significant increase in traction forces from 15.2±1.4 to 22.4±1.8nN was found by increasing the spacing of the microposts from 6μm to 10μm, although organization of stress fibers was less observed. This result indicates that, for the 10μm spacing, actomyosin interactions may be activated, producing higher traction forces per microposts. In addition, when microtubules were disrupted, a 30% increase in traction forces was observed in cells plated on both sets of microposts. This result suggests that the increase in traction forces after disruption of microtubules is mainly not due to an activation of actomyosin interactions but possibly due to structural changes caused by the loss of microtubules networks.