Plasma membrane permeabilization by 60‐ and 600‐ns electric pulses is determined by the absorbed dose

Abstract

We explored how the effect of plasma membrane permeabilization by nanosecond-duration electric pulses (nsEP) depends on the physical characteristics of exposure. The resting membrane resistance (R m ) and membrane potential (MP) were measured in cultured GH3 and CHO cells by conventional whole-cell patch-clamp technique. Intact cells were exposed to a single nsEP (60 or 600 ns duration, 0-22 kV/cm), followed by patch-clamp measurements after a 2-3 min delay. Consistent with earlier findings, nsEP caused long-lasting R m decrease, accompanied by the loss of MP. The threshold for these effects was about 6 kV/cm for 60 ns pulses, and about 1 kV/cm for 600 ns pulses. Further analysis established that it was neither pulse duration nor the E-field amplitude per se, but the absorbed dose that determined the magnitude of the biological effect. In other words, exposure to nsEP at either pulse duration caused equal effects if the absorbed doses were equal. The threshold absorbed dose to produce plasma membrane effects in either GH3 or CHO cells at either pulse duration was found to be at or below 10 mJ/g. Despite being determined by the dose, the nsEP effect clearly is not thermal, as the maximum heating at the threshold dose is less than 0.01 °C. The use of the absorbed dose as a universal exposure metric may help to compare and quantify nsEP sensitivity of different cell types and of cells in different physiological conditions. The absorbed dose may also prove to be a more useful metric than the incident E-field in determining safety limits for high peak, lowaverage power EMF emissions.

Effects of nanosecond pulsed electric field exposure on arabidopsis thaliana

“…It is reasonable, that the growth inhibiting effect is caused by electroporation of the plasmamembrane. In case of applying 100 ns pulses the impact on plant growth exhibits a clear dose dependency, typical for plasmamembrane permeabilization [29]. The higher the treatment energy the lower is the grown leaf area, Figure 5.…”

Nanosecond pulsed electric field thresholds for nanopore formation in neural cells

“…Nanopore formation, in contrast to the larger pores formed by longer pulses (electroporation), are less likely to pass large ions such as propidium, but freely allow passage of small ions. 7,8 Various studies using diverse techniques such as electrophysiology, [9][10][11] fluorescence microscopy, 7,11 and direct ion measurement in bulk solution for longer pulse widths 12 have supported the hypothesis that such "nanopores" exist. Interestingly, when exposed cells are under a whole cell patch clamp, nanopore activity appears to have unique electrical characteristics.…”

A microfluidic biochip for the nanoporation of living cells

“…Different works have reported about the effects on animal cells of these kinds of pulses, commonly named nanosecond pulsed electric fields (nsPEF). More precisely, it has been shown that the gene electrotransfection efficiency can be improved by nsPEF exposure, also called nanoporation, (Beebe et al 2003) and that disturbances on the cell membrane could be sufficient to render it permeable to small molecules, such as propidium iodide (Ibey et al 2009;Vernier et al 2006). Beyond their potential effects on the cell membrane, these nsPEF show a great interest because they also offer the possibility to disturb the intra cellular structures and functions (Beebe and Schoenbach 2005).…”