Low voltage pulses can induce apoptosis.
ABSTRACT Electroporation is used for gene transfection, drug delivery, and cell fusion. While studies have shown that high voltage electroporation induces apoptosis in vitro, a strong electric field can lower cell survival rates. As there are no published reports which have examined apoptotic properties associate with low voltage electric charges, we demonstrated for the first time that consecutive low voltage pulses with a voltage lower than the membrane breakdown threshold of human cells can increase the membrane potential to the threshold required to induce electroporation. This led to apoptosis through caspase pathways. Moreover, necrotic cell damage was less than that caused by high voltage pulses. Therefore, low voltage electroporation can be a suitable anticancer method.
- SourceAvailable from: Neoncheol Jung[show abstract] [hide abstract]
ABSTRACT: Electroporation is widely used to achieve gene transfection. A common problem in electroporation is that it has a lower viability than any other transfection method. In this study, we developed a novel electroporation device using a capillary tip and a pipette that was effective on a wide range of mammalian cells, including cell lines, primary cells, and stem cells. The capillary electroporation system considerably reduced cell death during electroporation because of its wire-type electrode, which has a small surface area. The experimental results also indicated that the cell viability was dependent on the change in pH induced by electrolysis during electroporation. Additionally, the use of a long and narrow capillary tube combined with simple pipetting shortened the overall time of the electroporation process by up to 15 min, even under different conditions with 24 samples. These results were supported by comparison with a conventional electroporation system. The transfection rate and the cell viability were enhanced by the use of the capillary system, which had a high transfection rate of more than 80% in general cell lines such as HeLa and COS-7, and more than 50% in hard-to-transfect cells such as stem or primary cells. The viability was approximately 70-80% in all cell types used in this study.Biosensors and Bioelectronics 05/2008; 23(9):1353-60. · 5.44 Impact Factor
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ABSTRACT: This is a brief introduction to the emerging field of irreversible electroporation in medicine. Certain electrical fields when applied across a cell can have as a sole effect the permeabilization of the cell membrane, presumable through the formation of nanoscale defects in the cell membrane. Sometimes this process leads to cell death, primarily when the electrical fields cause permanent permeabilization of the membrane and the consequent loss of cell homeostasis, in a process known as irreversible electroporation. This is an unusual mode of cell death that is not understood yet. While the phenomenon of irreversible electroporation may have been known for centuries it has become only recently rigorously considered in medicine for various applications of tissue ablation. A brief historical perspective of irreversible electroporation is presented and recent studies in the field are discussed.Technology in cancer research & treatment 09/2007; 6(4):255-60. · 1.94 Impact Factor
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ABSTRACT: Extremely large but very short (20 kV/cm, 300 ns) electric field pulses were reported recently to non-thermally destroy melanoma tumors. The stated mechanism for field penetration into cells is pulse characteristic times faster than charge redistribution (displacement currents). Here we use a multicellular model with irregularly shaped, closely spaced cells to show that instead overwhelming pore creation (supra-electroporation) is dominant, with field penetration due to pores (ionic conduction currents) during most of the pulse. Moreover, the model's maximum membrane potential (about 1.2 V) is consistent with recent experimental observations on isolated cells. We also use the model to show that conventional electroporation resulting from 100 microsecond, 1 kV/cm pulses yields a spatially heterogeneous electroporation distribution. In contrast, the melanoma-destroying pulses cause nearly homogeneous electroporation of cells and their nuclear membranes. Electropores can persist for times much longer than the pulses, and are likely to be an important mechanism contributing to cell death.Biochemical and Biophysical Research Communications 11/2006; 349(2):643-53. · 2.41 Impact Factor