Label-free electrochemical sensor to investigate the effect of tocopherol on generation of superoxide ions following UV irradiation

BACKGROUND: Generation of reactive oxygen species (ROS), triggered by ultraviolet radiation (UVR), is associated with carcinogenesis of the skin. UV irradiation induced superoxide anion (O2(•−)) is the key ROS involved in the cellular damage. The cytoprotective efficacy of an unknown anti-oxidant compound can be evaluated by analyzing the production of O2(•−) from treated cells. METHODS: In this study, a glass carbon electrode functionalized with nanotube@DNA-Mn3(PO4)2 composite was applied to quantitative determination of generation of highly unstable O2(•−) from the melanoma A375 cell line following UVR(UV, UVA and UVB). In addition, the cytoprotective efficacy of anti-oxidant α-tocopherol was evaluated by quantifying the production of O2(•−). RESULTS: The results showed that, UVR triggers generation of O2(•−) in melanoma A375 cells, and α-tocopherol is effective in diminishing the production of O2(•−) following UV irradiation. By comparing the conventional cell-survival assays results, we found that our simple and quick electrochemical sensing method can quantify O2(•−) generation through the biological activity of an anti-oxidant compound (α-tocopherol). CONCLUSION: Our label-free electrochemical quantification method for ROS (O2(•−) major) in cells facing UVR stress demonstrates its potential application for high-throughput screening of anti-oxidation compounds.