Bioelectrics--new applications for pulsed power technology

The possibility to control functions and membrane transport processes in biological cells by external pulsed electric fields offers new applications for pulsed power technology. One such application is prevention of biofouling, an effect that is based on reversible electroporation of cell membranes. Pulsed electric fields of several kilovolts per centimeter amplitude and submicrosecond duration have been found to prevent the growth of aquatic nuisance species on surfaces. Reversible electroporation is also used for medical applications, e.g., for delivery of chemotherapeutic drugs into tumor cells, for gene therapy and for transdermal drug delivery. Higher electric fields cause irreversible membrane damage. Pulses in the microsecond range with electric field intensities in the tens of kilovolts per centimeter are used for bacterial decontamination of water and liquid food. A new type of field-cell interaction utilizing nanosecond pulses with electric fields exceeding 50 kV/cm has been recently added to known bioelectric effects. Based on capacitive coupling to cell substructures, it has the potential to affect transport processes across subcellular membranes and may be used for gene transfer into cell nuclei. Other studies indicate that it triggers intracellular processes such as programmed cell death that can be used for cancer treatment. In order to generate the required electric fields for these processes, high-voltage high-current sources are required. The pulse duration needs to be short to prevent thermal effects. Pulse power technology is the enabling technology for this new field of bioengineering, which we have termed 'bioelectrics.' Index Terms--Electroporation, pulsed electric field methods, subcellular effects.