Nanoscale topography mediates the adhesion of F-actin

Using a controllable nanoengineered surface that alters the dynamics of filamentous actin (F-actin) adhesion, we studied the tunability of biomolecular surface attachment. By grafting aminated nanoparticles, NPs, with diameters ranging from 12 to 85 nm to a random copolymer film, precise control over surface roughness parameters is realized. The ability to selectively generate monodisperse or polydisperse features of varying size and areal density leads to immobilized, side-on wobbly, or end-on F-actin binding as characterized by total internal reflection fluorescence (TIRF) microscopy. The interaction between the surface and actin is explained by a worm-like chain model that balances the bending energy penalty required for actin to conform to topographical features with the electrostatic attraction engineered into the surface. A Myosin V motility assay demonstrates that electrostatically immobilized actin retains its ability to direct myosin motion, indicating that nanoengineered surfaces are attractive candidates for biomolecular device fabrication.