A rapid response time and highly sensitive amperometric glucose biosensor based on ZnO nanorod via citric acid-assisted annealing route

ZnO nanorods were synthesized by citric acid-assisted annealing route. In a phosphate buffer solution with a pH value of 7.4, glucose oxidase was immobilized on the surface of ZnO nanorod through chitosan-assisted cross-linking technique. The one-dimensional ZnO nanorods provide a large effective surface area with high surface-to-volume ratio and provide a favorable environment for the immobilization of GOx. The response time of this biosensor is less than 2 s. This biosensor has a very high sensitivity of 25.7 μA cm−2 mM−1. The low detection limit was estimated to be 0.01 mM. Two linear response ranges are 0.01–0.25 mM and 0.3–0.7 mM. The Michaelis–Menten constant is found to be 1.95 mM. These results demonstrate that zinc oxide nanorods have potential applications in biosensors.