Immobilization of Glucose Oxidase within Chitosan and Sol-Gel Matrix for Biosensors

Enzyme-modified electrodes were fabricated by entrapping glucose oxidase (GOx) and ferrocene (Fc) using chitosan membrane and sol-gel matrix. In chitosan membrane entrapment method, the ferrocene and glucose oxidase were coated sequentially on a glassy carbon electrode and entrapped by chitosan. In sol-gel matrix method, the ferrocene and glucose oxidase were embedded into sol-gel matrix without using any complicated linking processes. The prepared electrode was characterized by cyclic voltammetry (CV). Both Fc/GOx/CHI electrode and Fc/GOx/Sol-gel exhibited a good electrochemical performance for the glucose analysis. The response current of the both Fc/GOx/CHI and Fc/GOx/Sol-gel electrodes increased linearly with the increase of glucose concentration in the range of 0–10 mM glucose. The apparent Michaelis-Menten constants (Km) for the enzymes immobilized in the chitosan membrane and sol-gel matrix were observed to be 1.67 mM and 12.59 mM, respectively. The maximum current of the Fc/GOx/CHI and Fc/GOx/Sol-gel electrodes were 5.85 μA and 7.52 μA, respectively.