Development of an Electrochemical DNA Biosensor Based on Gold Nanoparticles and Thiol Graphene Nanocomposite for Detection of a Specific nuc Gene from Staphylococcus aureus

Background: An electrochemical DNA biosensor based on gold nanoparticles (AuNPs) and thiol graphene (TGR) nanocomposite modified carbon ionic liquid electrode (CILE) was developed to detect a specific nuc gene of Staphylococcus aureus, which was further used in the analysis of PCR amplification samples from unfrozen pork. Objective: The development of a DNA biosensor derived from AuNPs-coated TGR could be used as a novel sensing method for the detection of specific ssDNA sequences in biological and clinical samples. Methods: The electrochemical properties of modified CILE electrodes were determined by cyclic voltammetry and electrochemical impedance spectroscopy, and the electrochemical performances of the biosensor were investigated by differential pulse voltammetry. Results: This gene sensor was able to detect the specific nuc gene from Staphylococcus aureus over the concentration range from 1.00^-15 mol L^-1 to 1.00^-6 mol L^-1 with a limit of detection of 4.50^-16 mol L^-1 (3σ), and it was applied in the detection of Staphylococcus aureus in an unfrozen pork sample after PCR amplification of the nuc gene with satisfactory results. Conclusion: This gene biosensor showed high sensitivity and good selectivity, wide detection range and low detection limit, which demonstrated an effective tool to detect specific nuc gene sequences of Staphylococcus aureus.