Electroporation of cells and tissues

Electrical pulses that cause the transmembrane voltage of fluid lipid bilay er membranes to reach at least U-m approximate to 0.2 V, usually 0.5-1 V, a re hypothesized to create primary membrane "pores" with a minimum radius of similar to 1 nm, Transport of small ions such as Na+ and Cl- through a dyn amic pore population discharges the membrane even white an external pulse t ends to increase U-m, leading to dramatic electrical behavior. Molecular tr ansport through primary pores and pores enlarged by secondary processes pro vides the basis for transporting molecules into and out of biological cells , Cell electroporation in vitro is used mainly for transfection by DNA intr oduction, but many other interventions are possible, including microbial ki lling. Ex vivo electroporation provides manipulation of cells that are rein troduced into the body to provide therapy. In vivo electroporation of tissu es enhances molecular transport through tissues and into their constituativ e cells, Tissue electroporation, by longer, large pulses, is involved in el ectrocution injury. Tissue electroporation by shorter, smaller pulses is un der investigation for biomedical engineering applications of medical therap y aimed at cancer treatment, gene therapy, and transdermal drug delivery. T he tatter involves a complex barrier containing both high electrical resist ance multilamellar lipid bilayer membranes and a tough, electrically invisi ble protein matrix.