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Advisor(s)
Abstract(s)
Reactive oxygen species (ROS) are produced as a consequence of normal aerobic metabolism and are
able to induce DNA oxidative damage. At the cellular level, the evaluation of the protective effect of
antioxidants can be achieved by examining the integrity of the DNA nucleobases using electrochemical
techniques. Herein, the use of an adenine-rich oligonucleotide (dA21) adsorbed on carbon paste electrodes
for the assessment of the antioxidant capacity is proposed. The method was based on the partial damage
of a DNA layer adsorbed on the electrode surface by OH• radicals generated by Fenton reaction and
the subsequent electrochemical oxidation of the intact adenine bases to generate an oxidation product
that was able to catalyze the oxidation of NADH. The presence of antioxidant compounds scavenged
hydroxyl radicals leaving more adenines unoxidized, and thus, increasing the electrocatalytic current of
NADHmeasured by differential pulse voltammetry (DPV). Using ascorbic acid (AA) as a model antioxidant
species, the detection of as low as 50nMof AA in aqueous solution was possible. The protection efficiency
was evaluated for several antioxidant compounds. The biosensor was applied to the determination of the
total antioxidant capacity (TAC) in beverages.
Description
Keywords
NADH DNA biosensor Electrocatalytic oxidation Total antioxidant capacity (TAC) Ascorbic acid Reactive oxygen species (ROS)
Citation
Publisher
Elsevier