Biological/medical pulsed electric field treatments

The application of electric fields to a medium, which contains biological cells, causes build-up of charges at the cell membrane, and consequently a change in the transmembrane potential of cells. For low electric fields, this causes voltage-gating, the voltage-induced opening of channels in the cell membrane. With increasing electric field, at transmembrane voltages on the order of 1 V, the cell membrane becomes permeable, an effect called electroporation. It is reversible for moderate electric fields (kV/cm) and pulse duration of microseconds to milliseconds. At higher fields and/or longer pulse durations the cells will be lysed. Applications of these outer membrane effects are biofouling prevention, medical applications such as electroporative delivery of chemotherapeutic drugs into tumor cells, gene therapy, transdermal drug delivery and bacterial decontamination of drinking water and liquid food. A new type of field-cell interaction, "intracellular electromanipulation" by means of submicrosecond electrical pulses at electric fields exceeding 50 kV/cm has been recently added to known cellular bioelectric effects. The bioelectric technique, which is based on high frequency field-cell interactions, extends electroporation of the outer cell membrane to subcellular structures.