The temporal dynamics of electroporation of cells subjected to ultrashort voltage pulses are studied based on a coupled scheme involving the Laplace, Nernst-Plank, and Smoluchowski equations. A pore radius dependent energy barrier for ionic transport, accounts for cellular variations. It is shown that a finite time delay exists in pore formation, and leads to a transient overshoot of the transmembrane potential $V_{\mathrm{mem}}$ beyond 1.0 V. Pore resealing is shown to consist of an initial fast process, a ${10}^{-4}\mathrm{s}$ delay, followed by a much slower closing at a time constant of about ${10}^{-1}\mathrm{s}.$ This establishes a time-window during which the pores are mostly open, and hence, the system is most vulnerable to destruction by a second electric pulse. The existence of such a time window for effective killing by a second pulse is amply supported by our experimental data for E. coli cells. The time constant for the longer process also matches experiments. The study suggests that controlled manipulation of the pore “open times” can be achieved through multiple, ultrashort pulses.

• Received 6 February 2001

DOI:https://doi.org/10.1103/PhysRevE.64.011913