A novel effective immobilization of glucose oxidase on Ni0.25Zn0.25Cu0.25Co0.25La0.06Fe1.94O4 – Chitosan nanocomposite as an enzymatic glucose biosensor

Abstract

An effectual enzymatic glucose biosensor has drawn significant attention in the natural world due to its continuous glucose monitoring systems on human beings. A need for accurate and dependable glucose biosensors is needed and has notably augmented the keen interest to synthesize new non-invasive glucose monitoring systems in the recent phase. A novel Ni<inf>0.25</inf>Zn<inf>0.25</inf>Cu<inf>0.25</inf>Co<inf>0.25</inf>La<inf>0.06</inf>Fe<inf>1.94</inf>O<inf>4</inf> nanocomposite has been synthesized via the combustion method to develop an appreciable glucose biosensor. The glucose biosensor was fabricated by immobilization of glucose oxidase (GO<inf>x</inf>) onto chitosan (CH)-Ni<inf>0.25</inf>Zn<inf>0.25</inf>Cu<inf>0.25</inf>Co<inf>0.25</inf>La<inf>0.06</inf>Fe<inf>1.94</inf>O<inf>4</inf> heterojunction nanocomposite on FTO glass substrate. The performance of the as-prepared enzymatic glucose biosensor was estimated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical studies revealed an enhanced diffusion of molecules on the electrode surface, superior charge transfer rate, high sensitivity, and fast response time. The Ni<inf>0.25</inf>Zn<inf>0.25</inf>Cu<inf>0.25</inf>Co<inf>0.25</inf>La<inf>0.06</inf>Fe<inf>1.94</inf>O<inf>4</inf>-CH bi-junction conjoining with GOx exhibits a higher sensitivity of 52.76 µAmM-1cm−2 in a comprehensive undeviating range. The catalytic properties of the electrode in the H<inf>2</inf>O<inf>2</inf> solution were studied using cyclic voltammetry, which showed a good linear response with an increase in scan rate and peak current resulting in enriched electrostatic interaction. In addition, the fabricated biosensor with a low Michaelis-Menten constant contributes a better affinity of the electrode surface towards glucose oxide. © 2023 Elsevier B.V.