THE EFFECT OF PULSED ELECTRIC-FIELDS ON BIOLOGICAL CELLS - EXPERIMENTS AND APPLICATIONS

The effect of pulsed electric fields with amplitudes in the range of 1 00 V/cm-100 kV/cm on bacteria and aquatic nuisance species has been ex plored, The pulse duration was so short that heating of the biological matter could be neglected, The electrical energy required for lysing of bacteria, or stunning of aquatic species, decreases when the pulse duration is reduced, For lysing of Eschericia call, this tendency has been proven to hold for pulsewidths as short as 60 ns, For macroorgani sms, however, it was found that for pulsewidths of less than 5 mu s, t he tendency is reversed: the energy required to affect the macroorgani sms increases again, This minimum in energy, or maximum in efficiency, respectively, can be understood by taking the time required for elect rical charging of the cell membrane into account, Applications of the pulsed electric field technique (PEFT) are in biofouling prevention, d ebacterialization of liquids, and in the field of medicine. A series o f field tests on biofouling prevention in a cooling system with untrea ted water as coolant has demonstrated the economic feasibility of the electrotechnology.