PEDOT:PSS coated electrodes reduce intracellular oxidation and cell damage with pulsed electric field application

Abstract

Glioblastoma Multiforme is a highly lethal form of brain cancer, resistant to traditional therapeutic approaches and oftentimes hardly resectable. The application of pulsed electric fields (PEF) is gaining prominence as a highly effective approach for combating malignant tumors. However, PEF application at high voltages can generate reactive oxygen species through electrochemical events at electrodes, which can greatly affect intracellular processes and damage healthy cells. Here, we present an in depth study on the cellular impact of coating metal electrodes with an organic polymer PEDOT:PSS. We compared the effect of PEF application through coated and uncoated gold electrodes on the U87 human glioblastoma cell line. The results show that PEF application using PEDOT:PSS-coated electrodes does not induce intracellular ROS generation, even at high voltages, contrary to that observed with uncoated electrodes. PEF delivery with PEDOT:PSS coated electrodes results in minimal cell electroporation and a lower intracellular calcium response than uncoated metal electrodes. The application of the antioxidant MnTBAP allowed us to establish that superoxide generation is partially responsible for the higher intracellular calcium response observed in uncoated metal electrodes. The results demonstrate that PEDOT-coated electrodes allow for PEF application without intracellular ROS generation, with the trade-off being a diminished electroporation efficiency. These electrodes could therefore be useful for PEF application in ROS-sensitive tissues, as well as for disentangling the effect of PEFs on cells from the metabolic impact of electrolytic events arising from the electrode material.

Keywords: Electroporation; Mitochondrial superoxide; PEDOT:PSS; Pulsed electric field.