Characterization of immobilization of an enzyme in a modified Y zeolite matrix and its application to an amperometric glucose biosensor.

A new approach to construct an amperometric biosensor is described. Without using bovine serum albumin-glutaraldehyde, glucose oxidase (GOx) was immobilized on a dealuminized Y zeolite (DAY)-modified platinum electrode to construct a glucose sensor. The large specific surface area of the zeolite substrate resulted in high enzyme loading. The immobilized GOx in this manner was stable and could maintain its high activity for at least 3 months. The interactions between the zeolite and the enzyme were investigated by means of Fourier transform infrared spectra, and the pore distribution and the surface acid property of DAY were preliminarily studied. The results showed that the hydrophilic property and the existing mesopores of DAY played important roles in the enzyme immobilization. This resulting biosensor exhibited good reproducibility and selectivity, owing to the uniform pore structure and unique ion-exchange property of the zeolite. The biosensor responded rapidly to glucose in the linear range from 2.0 x 10(-6) to 3.0 x 10(-3) M, with a detection limit of 0.5 microM.