We developed an amperometric glucose biosensor based on glucose oxidase (GOx) embedded in zinc oxide (ZnO)-chitosan (CS) hybrid composite films on electrodeposited Pt-Fe(III). This sensor exhibited a fast amperometric response (less than 10 s) to glucose, linearity from 10 μM to 11.0 mM of glucose with a detection limit of 1.0 μM (S/N = 3) and sensitivity of 30.70 μA mM-1 cm-2. An apparent Michaelis-Menten constant of 5.19 mM indicated high affinity between glucose and GOx immobilized in the ZnO-CS films. The effect of interferences such as uric acid, ascorbic acid, and acetaminophen on the performance of this sensor was negligible. In addition, this sensor retained 87% of its initial performance after two weeks of storage at 4°C, indicating that the hybrid composite films allowed successful immobilization of GOx with its high enzymatic activity.
Keywords: Glucose biosensor; chitosan; composite film; glucose oxidase; zinc oxide.