Simultaneous electrochemical detection of guanine and adenine using reduced graphene oxide decorated with AuPt nanoclusters.

A rapid and sensitive electrochemical sensing platform is reported based on bimetallic gold-platinum nanoclusters (AuPtNCs) dispersed on reduced graphene oxide (rGO) for the simultaneous detection of guanine and adenine using square wave voltammetry (SWV). The synthesis of AuPtNCs-rGO nanocomposite was achieved by a simultaneous reduction of graphene oxide (GO) and metal ions (Au3+ and Pt4+) in an aqueous solution. The developed AuPtNCs-rGO electrochemical sensor with the optimized 50:50 bimetallic (Au:Pt) nanoclusters exhibited an outstanding electrocatalytic performance towards the simultaneous oxidation of guanine and adenine without the aid of any enzymes or mediators in physiological pH. The electrochemical sensor platform showed low detection limits of 60 nM and 100 nM (S/N = 3) for guanine and adenine, respectively, with high sensitivity and an extensive linear range from 1.0 μM to 0.2 mM for both guanine and adenine. The interference from the most common electrochemically active interferents, including ascorbic acid, uric acid, and dopamine, was almost negligible. The simultaneous sensing of guanine and adenine in denatured Salmon Sperm DNA sample was successfully achieved using the proposed platform, showing that the AuPtNCs-rGO nanocomposite could provide auspicious clinical diagnosis and biomedical applications.