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Electrochemical Biosensor Based on Nicotinamide Adenine Dinucleotide/Gold Nanoparticles Composite for Determination of the Antioxidant Activity of Caffeic Acid |
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PP: 51-58 |
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Author(s) |
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Emad F. Newair,
Refat Abdel-Hamid,
Ayman Nafady,
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Abstract |
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| As a consequence of normal aerobic metabolism, reactive oxygen species (ROS) are produced and induce DNA oxidative damage. The evaluation of the protective effect of antioxidant caffeic acid (CAF)was achieved by examining the integrity of the DNA nucleobases using square wave voltammetry (SWV). Herein, anelectrochemical biosensor based on nicotinamide adenine dinucleotide (NADH) was used for the assessment of the antioxidant activity. The biosensor was constructed via successive voltammetric scanning of a 0.9 µM NADH solution using glassy carbon electrode modified with gold nanoparticles(AuNPs/GCE)in 0.2 M phosphate-buffer saline (PBS) at room temperature. The method was based on the partial damage of a NADH layer adsorbed on the electrode surface by OH• radicals generated by Fenton reaction. Upon immersion of the sensor in Fenton solution mixture, current response is decreased due to competitive interaction between NADH with the hydroxyl radicals and the direct oxidation of NADH on the electrode. On addition of CAF, the oxidation response is increased. This is attributed to the scavenging of the hydroxyl radicals by CAF leaving more adenines unoxidized, and thus, increasing the electrocatalytic current of NADH. The caffeic acid scavenging percentage to •OH was evaluated. The results show that the scavenging potency of CAF is best at 50.0 µM and calculated to be 66.92 %. |
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