Electrochemical DNA biosensor for detection of DNA damage induced by hydroxyl radicals.
A simple electrochemical DNA biosensor based on a glassy carbon electrode (GCE) was prepared by adsorbing double-stranded DNA (dsDNA) onto the GCE surface and subsequently used for the detection of dsDNA damage induced by hydroxyl radicals. Investigation of the mutual interaction between hydroxyl radicals and dsDNA was conducted using a combination of several electrochemical detection techniques: square-wave voltammetry for direct monitoring the oxidation of dsDNA bases, and cyclic voltammetry and electrochemical impedance spectroscopy as indirect electrochemical methods making use of the redox-active indicator [Fe(CN)6]4-/3-. Hydroxyl radicals were generated electrochemically on the surface of a boron-doped diamond electrode and chemically (via the Fenton's reaction or the auto-oxidation of Fe(II)). The extent of dsDNA damage by electrochemically generated hydroxyl radicals depended on the current density applied to the generating electrode: by applying 5, 10, and 50mAcm-2, selected relative biosensor responses decreased after 3min incubation from 100% to 38%, 27%, and 3%, respectively. Chemically generated hydroxyl radicals caused less pronounced dsDNA damage, and their damaging activity depended on the form of Fe(II) ions: decreases to 49% (Fenton's reaction; Fe(II) complexed with EDTA) and 33% (auto-oxidation of Fe(II); Fe(II) complexed with dsDNA) were observed after 10min incubation.
Charles University, Faculty of Science, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Hlavova 2030/8, 128 43 Prague 2, Czech Republic. Electronic address: andrea.hajkova@natur.cuni.cz.
Andrea
A
Hájková
Charles University, Faculty of Science, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Hlavova 2030/8, 128 43 Prague 2, Czech Republic.
Jiří
J
Barek
Charles University, Faculty of Science, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Hlavova 2030/8, 128 43 Prague 2, Czech Republic. Electronic address: vlastimil.vyskocil@natur.cuni.cz.
Vlastimil
V
Vyskočil
D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004249:DNA Damage; D004563:Electrochemistry; D004566:Electrodes; D005898:Glass / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000494:pharmacology*; D007501:Iron / Q000737:chemistry
C045076:Fenton's reagent; D017665:Hydroxyl Radical; D002244:Carbon; D004247:DNA; D006861:Hydrogen Peroxide; D007501:Iron
Auto-oxidation; Boron-doped diamond electrode; Electrochemical DNA biosensor; Fenton's reaction; Glassy carbon electrode; Hydroxyl radicals