Evaluation of corrosion behaviors and surface profiles of platinum-coated electrodes by electrochemistry and complementary microscopy: Biomedical implications for anticancer therapy

Corrosion behaviors and surface profiles of platinum (Pt)-coated electrodes were investigated by electrochemistry and complementary microscopy. Four types of needle electrodes (Pt/titanium, Pt/tungsten, Pt/brass, and Pt/stainless steel) were prepared by unbalanced magnetron sputtering and subjected to the potentiodynamic polarization test in 0.9% deaerated sodium chloride solution at room temperature. The potentiodynamic test revealed that Pt/Ti electrodes had the highest corrosion resistance among the electrodes tested in this study, with the corrosion potential of 228 mV_SCE and the corrosion rate of 0.10 μA/cm². Morphology and surface profiles of the electrodes examined by reflected light, electron, and atomic force microscopy were consistent with those of corrosion resistance, showing that the electrodes with higher corrosion resistance had lower surface roughness than others. It is likely that the electrodes with higher corrosion resistance have suffered slower dissolution of substrates, and consequently had less cavities and/or corrosion products. Furthermore, nude mice inoculated with a bronchoalveolar cancer cell line and exposed to direct electric field showed the deterioration of proliferated tumor cells, proving the efficacy of electrochemical treatment. These results suggest that either Pt/Ti or Pt/W electrodes for solid tumors are suitable to be employed in the electrochemical treatment of tumors for anticancer therapy, applying low-level direct current due to their high corrosion resistance.