A new nanocomposite-based screen-printed graphene electrode for sensitive and selective detection of 8-hydroxy-2′-deoxyguanosine

[Display omitted] •A new nanocomposite-based electrochemical sensor for the determination of 8-hydroxy-2'-deoxyguanosine was presented.•First time synergistic employment of gold nanoparticles and poly(L-methionine)-modified screen-printed graphene electrode for 8-OHdG sensing.•Sodium phosphate buffer solution containing sodium chloride and sodium dodecyl sulfate was used as the supporting electrolyte for specific detection of 8-OHdG.•The effect of interferences, particularly uric acid and chloride ions at normal levels from 8-OHdG detection, was reported.•This sensing platform provides simple operation, effective cost, good selectivity, and high potential for screening 8-OHdG in early diagnosis. 8-Hydroxy-2′-deoxyguanosine (8-OHdG) is a crucial marker used to appraise the degree of endogenous oxidative DNA damage in the human body. For routine clinical analysis, a simple, rapid, cost-effective, reliable, selective, sensitive, and portable approach is exceedingly required. In this work, we first reported on the fabrication of an electrochemical sensor based on poly(L-methionine) and gold nanoparticle-modified screen-printed graphene electrode (poly(L-Met)/AuNPs/SPGE) for the sensitive and selective detection of 8-OHdG in the presence of uric acid at a normal level in urine, which is the major interference when using square wave voltammetry. Sodium phosphate buffer solution containing sodium chloride and sodium dodecyl sulfate was used as the supporting electrolyte for specific detection of 8-OHdG. The oxidation peaks of 8-OHdG and uric acid can be obviously separated. Under optimal conditions, the linearity between the anodic peak current and the 8-OHdG concentration was obtained within the range of 1–50 µM, and the limit of detection (3SD/Slope) and limit of quantification (10SD/Slope) were found to be 92 and 306 nM, respectively. This fabricated sensor was successfully applied to determine the 8-OHdG concentration in biological fluid samples with good selectivity, sensitivity, reliability, reproducibility, accuracy, and precision. The promising results demonstrated that this proposed methodology could be useful for medical personnel in diagnosing the disease risk from 8-OHdG levels at an early stage.