Detection of superoxide anion radical in a stratum corneum intercellular lipid model using an electrochemical sensor

A stratum corneum intercellular lipid model was prepared in a quasi-non-aqueous system. It was found that the detection of the superoxide anion radical (O₂⁻•) generated in the lipid model by ultraviolet (UV) irradiation was possible using an electrochemical O₂⁻• sensor. The use of an electron spin resonance-spin trap method confirmed that the reactive oxygen species generated in the lipid model by UV irradiation was O₂⁻•; the presence of a hydroxyl radical (•OH) was also proven. In addition, a reduction in the electric current in the O₂⁻• sensor was observed in lipid models containing added antioxidants such as d-α-tocopherol and β-carotene. Moreover, there was a correlation between the degree of oxidative degradation of the lipid, which was determined by the thiobarbituric acid method, and the electric current due to the O₂⁻• detected using the O₂⁻• sensor.