title: Diffusion of actin filaments within a thin layer between two walls.
abstract: Diffusion of the protein filaments F -actin confined in a thin layer between two walls is studied using the methods of single filament fluorescence imaging and particle tracking. The translational and rotational diffusion coefficients are measured for F -actin of lengths in the range of 1.5-5 microm. The length dependence of the measured diffusion coefficients is consistent with the predicted two-dimensional projection of the diffusion of a cylinder in an unbounded fluid. Fits based on the formulas for diffusion in the bulk fluid yield higher apparent viscosity values than that of the buffer solution by a factor of 2 for a layer thickness between 0.7 and 1.6 microm. We show that the measured results can be accounted for by correction based on the hydrodynamic theory of a long cylinder between confining walls.
authors.affiliation: Physics Department, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Guanglai
authors.initials: G
authors.lastname: Li
authors.forename: Jay X
authors.initials: JX
authors.lastname: Tang
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000648:ultrastructure*; D003198:Computer Simulation; D004058:Diffusion; D044085:Microfluidics / Q000379:methods*; D008956:Models, Chemical; D009038:Motion; D012996:Solutions
chemical_list: D000199:Actins; D012996:Solutions