The birth, life and death of statistical pores into a bilayer membrane

There is a significant evidence indicating that pores of nanoscopic dimensions can stochastically form and grow in a lipid bilayer of a cell membrane following an activated process induced by an external trigger such as thermal fluctuations, transmembrane electrical potential, mechanical stress or other changes in the cellular environment. In this review article, we present an overview of recent theoretical and experimental developments to better understand the mechanisms responsible for stochastic pore Correspondence/Reprint request: Dr. Liviu Movileanu, Laboratory of Single-Molecule Biophysics, Syracuse University Department of Physics, 201 Physics Building, Syracuse NY 13244-1130, USA. E-mail: [email protected] Liviu Movileanu & Dumitru Popescu 62 formation. A transient pore may open or close, thus the final pore state and its kinetics are dependent on the forces that act on the pore boundary. These are: (1) the surface tension, which reduces the free energy barrier for pore formation, and (2) line tension, which increases the free energy barrier for pore formation.The recent results regarding the kinetics of pore opening and resealing are also discussed. The pore formation in a membrane has multiple projected applications including drug delivery and gene therapy. Several experimental strategies were examined, such as the use of a suitable chemical agent, pore-forming peptides, electroporation, temperature jump or osmotic shock to bring about an increase in membrane permeability for DNA or drug molecules.