Tracking single molecular diffusion on glass substrate modified with periodic Ag nano-architecture

Diffusion of individual dye-labeled, molecules in self-spreading lipid bilayer on glass substrate in aqueous solution was observed directly using total internal reflection fluorescence microscopy (TIRFM). The molecular diffusion was evaluated quantitatively by the mean square displacement (MSD) analysis for the trajectories of individual molecules. The mode of normal Brownian diffusion in lipid bilayer was changed in the presence of the periodic triangular Ag nanoparticles on the surface of the substrate. Suppressed diffusivity observed at the system with the triangular Ag nanoparticles was attributed to the confinement of the molecular motion in the micro-compartment surrounded by the Ag triangles.