Are the stainless steel electrodes inert?

The electrodes used for electroporation, electrofusion, and electrotransfec tion, as well as in electrochemotherapy should not interact with the object and release electrolysis products. We studied how far the stainless steel electrodes fulfil these requirements. The results showed that in the case o f the exponential electric pulses with amplitude of 3 kV cm(-1) and time co nstant of 0.5 ms, the stainless steel electrodes released ferrous ions to a concentration of several micromoles per liter. We determined experimentall y the dependence of the amount of the released ferrous ions on the pulse pa rameters and on the ionic strength of the medium. It was shown that the rel eased ferrous ions should not be ignored. They could be of importance for t he bleomycin electrochemotherapy. (C) 2000 Elsevier Science S.A. All rights reserved.