A QUANTITATIVE STUDY OF ELECTROPORATION SHOWING A PLATEAU IN NET MOLECULAR-TRANSPORT

Electroporation is believed to involve a temporary structural rearrang ement of lipid bilayer membranes, which results in ion and molecular t ransport across the membrane. The results of a quantitative study of m olecular transport due to electroporation caused by a single exponenti al pulse are presented; transport of four molecules of different physi cal characteristics across erythrocyte ghost membranes is examined as a function of applied field strength. Flow cytometry is used to quanti tatively measure the number of molecules transported for 104 to 105 in dividual ghosts for each condition. This study has four major findings : 1) Net transport first increases with field strength, but reaches a plateau at higher field strengths. Significant transport is found at o r below 1 kV/cm, and transport plateaus begin at field strengths betwe en 2 and 5 kV/cm depending on the molecule transported. 2) A single po pulation of ghosts generally exists, but exhibits a wide distribution in the amount of molecular transport. 3) Under the conditions used, th e direction of transport across the ghost membrane does not appear to affect molecular transport significantly. 4) Large numbers of ghosts m ay be destroyed by the electroporation procedure.