Highly stable biosensor based on glucose oxidase immobilized in chitosan film for diagnosis of diabetes

In this work, a highly stable electrochemical biosensor was fabricated by biomaterials for determination of glucose in the aqueous phase. Chitosan (CHIT) was used for immobilization of glucose oxidase (GOx) on the surface of platinum (Pt) electrode. The performance of the fabricated biosensor was assessed by cyclic voltammetry and amperometry. The modified electrode showed an excellent performance for glucose detection with a short response time of 5 s, high sensitivity of 38.5 mu A mM(-1) cm(-2), the linear range of 2 x 10(-4)-9.1 x 10(-3) M and detection limit of 7.4 mu M glucose at a signal to noise ratio of 3. The low value (11.3 mM) of the apparent Michaelis-Menten constant(KM) indicated that the biosensor had a high affinity to glucose. The effect of temperature on the amperometric response was investigated to evaluate the thermal stability of the biosensor. The study of the long-term stability of biosensor revealed that the modified electrode retained 97% of its initial current response after 30 days. The obtained results showed that CHIT enhanced anti-interference ability, and the thermal and long-term stability of the biosensor.