Influence of iron ions and hydrogen peroxide on the fluorescence of amplex red dye quenching and CHO cells viability

Abstract

Fluorescent probes provide a convenient, sensitive and versatile means for studying cell membrane electropermeabilization [1]. When cell suspension is exposed to high–voltage electric pulses, besides cell membrane permeabilization, various electrochemical reactions occur at electrode–solution interfaces. These may include evolution of gases (H2, O2, Cl2), changes of pH, dissolution of electrodes (releasing metal ions), formation of hypochloride acid, free radicals, reactive oxygen species (ROS) [2]. Metal ions, released from the electrodes during a high-voltage pulse, and ROS such as hydrogen peroxide (H2O2) can react with the fluorescent dyes and quench their fluorescence [3, 4]. This may have an impact, when estimating the efficiency of cell eletropermeabilization. In this study, the influence of iron ions and hydrogen peroxide on the fluorescence of Amplex Red dye as well as on the viability of CHO cell was studied. With increasing the concentration of the iron ions in the solution the intensity of the fluorescence of Amplex Red decreased. For example, 1 mM of Fe3+ ions suppressed fluorescence of Amplex Red by 30–50%. Also the reduction of the viability of CHO cells by iron ions and hydrogen peroxide has been demonstrated. The results of this work can be useful for optimizing the electroporation methods used in biotechnology, medicine, and food industry.