Electroporation

CONTENTS 9.1 Background...................................................................................................................... 293 9.2 Pore Models of Planar Lipid Bilayer Electromechanical Behavior ........................ 296 9.3 Cell Membrane Electromechanical Phenomena ........................................................ 298 9.4 Nonpore Theories of Electromechanical Phenomena............................................... 299 9.5 Pore Theories of Electromechanical Phenomena....................................................... 300 9.6 Molecular and Ionic Transport..................................................................................... 305 9.7 Electrotransfection .......................................................................................................... 310 9.8 Membrane Recovery....................................................................................................... 312 9.9 Cell Stress and Survival................................................................................................. 314 9.10 Tissue Electroporation and In Vivo Delivery ............................................................. 315 9.11 Electroporation of Organelles ....................................................................................... 319 Acknowledgment....................................................................................................................... 320 References ................................................................................................................................... 321

Cells and tissues contain multiple, spatially distributed barriers that compartmentalize charged and large molecules. These barriers are largely constructed out of lipids, usually phospholipids. For this reason, only very small molecules with effective high lipid solubility spontaneously penetrate the single or double phospholipid bilayerbased membranes of cells and and their organelles [1]. Of course, these membranes have a large variety of channels and transporters that facilitate transport of particular ions and molecules. Other significant barriers consist of one or more layers of cells connected by tight junctions around bladders and ducts that help retain specialized fluids, and the tough, flexible stratum corneum of mammalian skin that prevents water loss, entry of toxic molecules and infectious agents. Electroporation results in an essentially universal physical reduction of such barriers by creating membrane-spanning aqueous pathways. Aqueous pathways (large dielectric constant «w 80) across lipidcontaining (small dielectric constant «1 2) barriers greatly favor transport of even small, monovalent ions [2,3].