Effect of surface chemistry on in vitro actomyosin motility

A variety of surface coatings were evaluated for their ability to promote in vitro actomyosin motility. Rabbit skeletal muscle heavy meromyosin (HMM) was adsorbed to uncoated glass and to surfaces coated with nitrocellulose, poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), poly(tert-butyl methacrylate (PtBMA), polystyrene (PS) and hexamethyldisilazane (HMDS), and the myosin driven movement of fluorescently labeled actin filaments was recorded using epifluorescence microscopy. HMDS and uncoated glass did not support actomyosin motility, while mean velocities on other surfaces ranged from 1.7 mu m sec(-1) (PtBMA) to 3.5 mu m sec(-1) (NC). Nitrocellulose supported the highest proportion of motile filaments (75%), while 47 - 61% of filaments were motile on other surfaces. Within the methacrylate polymers, average filament velocities increased with decreasing hydrophobicity of the surface. Distributions of instantaneous acceleration values and angle deviations suggested more erratic and stuttered movement on the methacrylates and polystyrene than on NC, in line with qualitative visual observations. Despite the higher velocities and high proportion of motile filaments on NC, this surface resulted in a high proportion of small filaments and high rates of filament breakage during motility. Similar effects were observed on PS and PtBMA, while PBMA and PMMA supported longer filaments with less observed breakage.