Electrochemical Sensor Platform for 8-Hydroxy-2′- Deoxyguanosine Detection Based on Carboxyl-Functionalized Carbon-Allotropic Nanomaterials Wrapped Gold Nanoparticles Modified Electrode

摘要

As a typical biomarker of oxidative DNA damage, 8-hydroxy-2′-deoxyguanine (8-OHdG) has receivedconsiderable attention in recent years, because elevated levels of urinary 8-OHdG are typicallyassociated with various diseases related to oxidative stress. However, the accurate identification andquantification of 8-OHdG in human urine is generally confounded by its trace content and complexmatrices. In this work, a facile and effective electrochemical sensor for urinary 8-OHdG detection wasconstructed based on carboxyl-functionalized carbon-allotropic nanomaterials (GO-COOH/MWCNTs-COOH) wrapped gold nanoparticles (Au NPs), which resulted in modified electrode. The sensingmaterial consisting of GO-COOH, MWCNTs-COOH, polyethyleneimine (PEI), and Au NPs wasfabricated by self-assembly of negatively charged Au NPs onto positively charged PEI-wrapped GO-COOH and MWCNTs-COOH through electrostatic interactions. The electrochemical experimentsdemonstrated that the biosensor showed high electrochemical performance on the oxidation of 8-OHdG and efficiently alleviated the interferences from uric acid (UA) with the help of uricase.According to differential pulse voltammetry (DPV) results, the oxidation peak currents correlatedlinearly with the concentration of 8-OHdG in the ranges of 0.014 - 0.14 μM (R 2 = 0.9916), 0.14 - 1.41μM (R 2 = 0.9954), and 1.41 - 14.12 μM (R 2 = 0.9915) with a detection limit (S/N = 3) of 7.06 nM. Inaddition, the results of analytical detection of 8-OHdG in human urine samples were satisfactory witha very high recovery percentage. Therefore, it is believed that the proposed sensor is a promisingcandidate for risk assessment of various diseases related to oxidative stress.