G. Saulis, A. Bitinaitė, R. Saulė, V. Stankevič, N. Žurauskienė, S. Balevičius
Vytautas Magnus University, Lithuania
pp. 156 - 160
Keywords: electroporation, potassium ions, absorbed dose, drug delivery
To successfully implement the technology of food processing with pulsed electric fields (PEF), it is important to know what particular electric treatment (pulse duration, field strength, etc.) would require the minimum energy. Here, theoretical relationships between the energy of PEF treatment required to electroporate cells and pulse duration were obtained for pulses of different shape. Theoretical analysis has been made assuming that the pore formation is a random one-step process. Experimental data for square-wave electric pulse were obtained on human erythro-cytes, mouse hepatoma MH-22A, rat glioma C6, and Chinese hamster ovary (CHO) cells. The fraction of electroporated MH-22A, C6, and CHO cells was determined from the extent of the release of intracellular potassium ions and human erythrocytes -- from the extent of their hemolysis after 20-24 h-incubation in 0.63% NaCl solution at 4 oC. These dependencies were determined for pulses with the duration from 40 ns to 2 ms and pulse amplitudes from 0.2 to 100 kV/cm. Theoretical dependencies are in good agreement with experimental ones: for pulses longer than 1 us, the energy required to electroporate the cells increases with increasing the pulse length, while for pulses shorter than 0.1-0.3 us the shorter the pulse, the higher the energy of an electric field pulse, which is required to electroporate the cells. There exists a minimum of the PEF treatment energy required to electroporate the cells. It depends on the cell size and is situated in the range of 0.1-1 us. A minimum of the PEF treatment energy is about 0.13 and 0.07 J/g for human erythrocytes (radius 3 um) and mouse hepatoma MH-22A cells (radius 7.7 um) respectively.