Characterization of the cellular biomechanlcal responses caused on microprocessed substrates: effect of micropatterned cell adhesiveness and microelasticity gradient

To investigate the shape-dependent cell mechanics and ECM-dependent control of motility, cell elasticity, structural features of the actin cytoskeleton (CSK) and motility responses were characterized on well-designed microprocessed substrates with micropatterned cell adhesive regions and microelastic gradient. Cell elasticity and actin CSK features of shape-engineered fibroblasts and vascular endothelial cells (round and spindle-shaped) cultured on photolithographically microprocessed surfaces were characterized employing the cellular microindentation test and fluorescence observation of actin CSK by the combination of atomic force microscopy (AFM) and fluorescence microscopy (FM). Condition of directional cell movement towards stiffer region, so called mechanotaxis, was studied on the photolithographically-microprocessed microelastic gradient gel (MEG gel). The interrelationships between cell elasticity, the structural features of actin CSK and engineered cell shape were analyzed as compared with control cells cultured on non-processed surfaces (termed naturally extended cells). The results showed that the elasticity of regionally restricted adhesion-surface-induced shape-engineered cells, particularly highly elongated cells, is predominantly affected by cell shape rather than by the structural features of SFs. As for the mechanotaxis behaviors induced on MEG gel, design of both elasticity jump and discreteness in the elasticity boundary was found to be essential to cause cellular directional movement