Article

Plasma membrane charging of Jurkat cells by nanosecond pulsed electric fields.

Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
Biophysics of Structure and Mechanism (Impact Factor: 2.47). 05/2011; 40(8):947-57. DOI: 10.1007/s00249-011-0710-7
Source: PubMed

ABSTRACT The initial effect of nanosecond pulsed electric fields (nsPEFs) on cells is a change of charge distributions along membranes. This first response is observed as a sudden shift in the plasma transmembrane potential that is faster than can be attributed to any physiological event. These immediate, yet transient, effects are only measurable if the diagnostic is faster than the exposure, i.e., on a nanosecond time scale. In this study, we monitored changes in the plasma transmembrane potential of Jurkat cells exposed to nsPEFs of 60 ns and amplitudes from 5 to 90 kV/cm with a temporal resolution of 5 ns by means of the fast voltage-sensitive dye Annine-6. The measurements suggest the contribution of both dipole effects and asymmetric conduction currents across opposite sides of the cell to the charging. With the application of higher field strengths the membrane charges until a threshold voltage value of 1.4-1.6 V is attained at the anodic pole. This indicates when the ion exchange rates exceed charging currents, thus providing strong evidence for pore formation. Prior to reaching this threshold, the time for the charging of the membrane by conductive currents is qualitatively in agreement with accepted models of membrane charging, which predict longer charging times for lower field strengths. The comparison of the data with previous studies suggests that the sub-physiological induced ionic imbalances may trigger other intracellular signaling events leading to dramatic outcomes, such as apoptosis.

0 Followers
 · 
123 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nanosecond electric pulses (nsEP) are defined as very short high intensity electric pulses which present great potential for the destabilization of intracellular structures. Their theoretical descriptions first suggested specific effects on organelles that have been confirmed by various observations both in vitro and in vivo. However, due to their concomitant effects on the plasma membrane, nsEP can also affect cell functions. In this mini-review, nsEP effects on cells are described following three topics: effects at the plasma membrane level, intracellular effects, and the impact on cell survival. Eventually, a short description of the major results obtained in vivo will be presented. This study shows that the use of nsEP has evolved during the last decade to focus on low voltage for practical applications.
    Bioelectrochemistry 08/2014; 103. DOI:10.1016/j.bioelechem.2014.07.008 · 3.87 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Electrofusion is an efficient method for fusing cells using short-duration high-voltage electric pulses. However, electrofusion yields are very low when fusion partner cells differ considerably in their size, since the extent of electroporation (consequently membrane fusogenic state) with conventionally used microsecond pulses depends proportionally on the cell radius. We here propose a new and innovative approach to fuse cells with shorter, nanosecond (ns) pulses. Using numerical calculations we demonstrate that ns pulses can induce selective electroporation of the contact areas between cells (i.e. the target areas), regardless of the cell size. We then confirm experimentally on B16-F1 and CHO cell lines that electrofusion of cells with either equal or different size by using ns pulses is indeed feasible. Based on our results we expect that ns pulses can improve fusion yields in electrofusion of cells with different size, such as myeloma cells and B lymphocytes in hybridoma technology.
    Scientific Reports 11/2013; 3:3382. DOI:10.1038/srep03382 · 5.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intense nanosecond pulsed electric fields (nsPEFs) interact with cellular membranes and intracellular structures. Investigating how cells respond to nanosecond pulses is essential for a) development of biomedical applications of nsPEFs, including cancer therapy, and b) better understanding of the mechanisms underlying such bioelectrical effects. In this work, we explored relatively mild exposure conditions to provide insight into weak, reversible effects, laying a foundation for a better understanding of the interaction mechanisms and kinetics underlying nsPEF bio-effects. In particular, we report changes in the nucleus of Jurkat cells (human lymphoblastoid T cells) exposed to single pulses of 60 ns duration and 1.0, 1.5 and 2.5 MV/m amplitudes, which do not affect cell growth and viability. A dose-dependent reduction in alkaline comet-assayed DNA migration is observed immediately after nsPEF exposure, accompanied by permeabilization of the plasma membrane (YO-PRO-1 uptake). Comet assay profiles return to normal within 60 minutes after pulse delivery at the highest pulse amplitude tested, indicating that our exposure protocol affects the nucleus, modifying DNA electrophoretic migration patterns.
    PLoS ONE 12/2011; 6(12):e28419. DOI:10.1371/journal.pone.0028419 · 3.53 Impact Factor