Anomalous Diffusion in Supported Lipid Bilayers Induced by Oxide Surface Nanostructures

Hierarchic structure and anomalous diffusion on submicrometer scale were introduced into an artificial cell membrane, and the spatiotemporal dependence of lipid diffusion was visualized on nanostructured oxide surfaces. We observed the lipid diffusion in supported lipid bilayers (SLBs) on step-and-terrace TiO2(100) and amorphous SiO2/Si surfaces by single molecule tracking (SMT) method. The SMT at the time resolution of 500 mu s to 30 ms achieved observation of the lipid diffusion over the spatial and temporal ranges of 100 nm/millisecond to 1 mu m/second. The temporal dependence of the diffusion coefficient in the SLB on TiO2(100) showed that the crossover from anomalous diffusion to random diffusion occurred around 10 ms. The surface fine architecture on substrates will be applicable to induce hierarchic structures on the order of 100 nm or less, which correspond to the microcompartment size in vivo.