Deep eutectic solvent-assisted synthesis of gold nanoflowers supported on glassy carbon electrode for DNA sensor application

Abstract

Gold nanoflowers (AuNF) were synthesized on a glassy carbon electrode via a one-step, eco-friendly protocol in deep eutectic solvent (DES) of choline choloride and urea, called reline, for label-free detection of DNA hybridization. DES is eco-friendly, low-cost, biocompatible, and nontoxic, and it can be used as an electrolyte to synthesize nanomaterials by using the electrochemical method. In this protocol, highly branched and stable AuNFs were obtained without using any surfactants for DNA sensor application. The electrochemical performance of the AuNF-modified electrode was studied by cyclic voltammetry and electrochemical impedance spectroscopy. Under optimal conditions, the AuNF-based DNA biosensor exhibited a sensitivity of 294.9 Ω nM−1cm−2 and 218 μA nM−1cm−2 and a limit of detection (LOD) of 10−9 M. The remarkable sensitivity and low LOD could be attributed to the good conductivity of AuNFs for accelerating electron transfer, resulting in obvious signal amplification. The DNA biosensor showed good reproducibility (RSD <3.65 %) and acceptable stability and selectivity. Its excellent performance in DNA detection suggested that the proposed electrochemical DNA sensor has great application potential in clinical diagnosis.