Au Nanoparticles on 4-Thiophenol-Electrodeposited Carbon Surfaces for the Simultaneous Detection of 8-Hydroxyguanine and Guanine

In this proof-of-concept study, gold nanoparticles (AuNPs) were immobilized on glassy carbon electrode (GCE) surfaces using a surface-anchored diazonium salt of 4-aminothiophenol (GCE-Ph-S-AuNPs). X-ray photoelectron spectroscopy (XPS) studies confirmed the attachment of the AuNPs via 4-thiophenol onto the surface of the modified electrode. Differential pulse voltammetry (DPV) was performed for the simultaneous determination of guanine (G) and 8-hydroxyguanine (8-OH-G). The calibration curves were linear up to 140 & mu;M and 60 & mu;M with a limit of detection of 0.02 & mu;M and 0.021 & mu;M for G and 8-OH-G, respectively. Moreover, chronoamperometric studies were carried out for the determination of diffusion coefficients of 8-OH-G and G. The GCE-Ph-S-AuNPs were also applied in genomic DNA-spiked samples for the determination of G and 8-OH-G with recovery rates between 98.5% and 103.3%. The novel electrochemical surface provided a potential platform for the sensitive detection of 8-OH-G related to oxidative stress-induced DNA damage in clinical studies.

Automated summary

In this proof-of-concept study, gold nanoparticles (AuNPs) were immobilized on a surface-modified glassy carbon electrode (GCE-Ph-S-AuNPs) using a surface-anchored diazonium salt of 4-aminothiophenol. The attachment of AuNPs onto the modified electrode surface was confirmed by X-ray photoelectron spectroscopy. Differential pulse voltammetry was performed to simultaneously determine guanine (G) and 8-hydroxyguanine (8-OH-G), with linear calibration curves up to 140 μM and 60 μM, and detection limits of 0.02 μM and 0.021 μM for G and 8-OH-G, respectively. Chronoamperometric studies were also conducted to determine the diffusion coefficients of 8-OH-G and G. The GCE-Ph-S-AuNPs were successfully applied to determine G and 8-OH-G in genomic DNA-spiked samples with recovery rates between 98.5% and 103.3%. This novel electrochemical surface provides a potential platform for the sensitive detection of 8-OH-G related to oxidative stress-induced DNA damage in clinical studies.