A biosensor for the sensitive and specific measurement of arsenite using gold nanoparticles

Abstract An electrochemical biosensor for arsenite concentration determination is developed in this study using arsenite oxidase (ArOx). Gold nanoparticles (AuNP) were used in this study to improve the analytical characteristics of the biosensor by providing a suitable nano-environment for the enzyme activity. The enzyme and the nanoparticles were electrodeposited on the glassy carbon (GC) working electrode to prepare the GC-AuNP-ArOx electrode. The linear measurement range of the biosensor was between 101-104 nM, while its detection limit was obtained equal to 5 nM. The effects of enzyme concentration, pH, storage temperature, and storage time on the biosensor’s performance were investigated. Results showed that an enzyme concentration of 7 μM at the physiological pH exerted the highest biosensor response (7 μA anodic current/10 nM arsenite). No undesirable interference of heavy metals was observed on the biosensor response, and the biosensor showed excellent reproducibility compared to a conventional chemosensor.