High-Resolution Characterization of Single Å-nm Scale Pores Revealed Dynamical Heterogeneity of Statistical Defects in Lipid Bilayer Membranes

Electric fields often lead to the opening of pores by activating statistical defects in lipid bilayer membranes. These electropores are ubiquitous in biology and are widely used in biotechnology and medicine. Our understanding of electropores has been limited by the poor time resolution of experiments, causing a discrepancy in the observed time scale of electropores. Here, using high-resolution ionic current measurements, we have characterized the μs-ms duration Å-nm scale single pores in the vertical bilayer membranes. Our experiments on over 2500 membranes revealed highly nonexponential kinetics of pores due to the dynamic heterogeneity of defects, and we were able to resolve the population of hydrophobic and hydrophilic pores, which were postulated before in theory but rarely resolved in experiments. Such dynamic heterogeneity of defects is likely a general feature of lipid membranes for selectively translocating diverse sets of molecules across cellular compartments on different time scales without requiring a receptor channel.