title: Electrochemical monitoring of native catalase activity in skin using skin covered oxygen electrode.
abstract: A skin covered oxygen electrode, SCOE, was constructed with the aim to study the enzyme catalase, which is part of the biological antioxidative system present in skin. The electrode was exposed to different concentrations of H2O2and the amperometric current response was recorded. The observed current is due to H2O2penetration through the outermost skin barrier (referred to as the stratum corneum, SC) and subsequent catalytic generation of O2by catalase present in the underlying viable epidermis and dermis. By tape-stripping the outermost skin layers we demonstrate that SC is a considerable diffusion barrier for H2O2penetration. Our experiments also indicate that skin contains a substantial amount of catalase, which is sufficient to detoxify H2O2that reaches the viable epidermis after exposure of skin to high concentrations of peroxide (0.5-1mM H2O2). Further, we demonstrate that the catalase activity is reduced at acidic pH, as compared with the activity at pH 7.4. Finally, experiments with often used penetration enhancer thymol shows that this compound interferes with the catalase reaction. Health aspect of this is briefly discussed. Summarizing, the results of this work show that the SCOE can be utilized to study a broad spectrum of issues involving the function of skin catalase in particular, and the native biological antioxidative system in skin in general.
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
authors.forename: Sarah
authors.initials: S
authors.lastname: Nocchi
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Björklund
authors.affiliation: Bioglan AB, SE-202 13 Malmö, Sweden.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Svensson
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Engblom
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden. Electronic address: tautgirdas.ruzgas@mah.se.
authors.forename: Tautgirdas
authors.initials: T
authors.lastname: Ruzgas
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D015374:Biosensing Techniques; D002374:Catalase / Q000737:chemistry / Q000302:isolation & purification*; D002384:Catalysis; D004566:Electrodes; D004817:Epidermis / Q000737:chemistry / Q000201:enzymology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000378:metabolism; D012867:Skin / Q000201:enzymology*
chemical_list: D000975:Antioxidants; D006861:Hydrogen Peroxide; D002374:Catalase; D010100:Oxygen
keywords: Antioxidative system; Catalase; Hydrogen peroxide; Oxygen electrode; Skin; Transdermal penetration