Vesicle and Lipid Bilayer Dynamics: Cross-Linking Effects and FRAP Analysis

Abstract

We investigate the effects of perturbations on lipid phase dynamics. Our primary tools are confocal microscopy and differential scanning calorimetry (DSC). In coexisting fluid two-phase vesicles we have characterized cross-linking in the fluid disordered phase. Instead of reaching thermodynamic equilibrium, we have documented an increase in meta-stable configurations. Using fluorescence recovery after photobleaching (FRAP), we investigate how cross-linking affects diffusion in lipid bilayer. The diffusion perturbations reveal that cross-linking and non-specific binding slows lateral mobility, which alters lipid dynamics. Since cell membranes are not at thermodynamic equilibrium, our investigations into the dynamics behavior are pertinent to understanding membrane response to common events, such as receptor-ligand complexing, glycosylation, and receptor platform formation.