Evaluation of Optimal Sub-Nanosecond Excitation Waveforms in Generating Transmembrane Voltages in Cells for Bio-Effects

Summary form only given. The use of very high electric fields (~500 kV/cm or higher) with pulse durations in the sub-nanosecond range has been a very recent development in bio-electrics. There appear to be inherent advantages in using short electric pulses such as: (i) negligible thermal heating, (ii) the possibility of selecting the desired time scales through pulse width manipulation, and (iii) the ability to create large trans-membrane potentials across subcellular organelles. This latter can effectively open the way to intra-cellular electromanipulation. The time-dependent transmembrane potential generated across cell membranes can be fashioned by the characteristics of the external excitation. However, at the present time it is not clear what the optimal waveform should be, or the efficiency of generating transmembrane potentials by the ultra-fast, subnanosecond pulses. From a practical standpoint, such excitation typically has "pre-pulses" and oscillatory components. In order to gauge possible bioeffects, an important first step in this subnanosecond arena appears to be theoretical predictions based on modeling. This contribution addresses this aspect. A theoretical analysis has been performed that includes variability m the excitation pulse waveform and details of the dielectric function leading to non-local effects in time. Results on the time-dependent evolution of the transmembrane potential will be presented. Extensions to multiple pulsing and implications for wave-shaping will be discussed.