Fiber-optic glucose biosensor based on glucose oxidase immobilized in a silica gel matrix

In this paper UV and visible intrinsic fluorescence measurements have been investigated in glucose oxidase (GOD) immobilized in a silica gel matrix as preliminary step for the development of an optical biosensor for glucose quantitative determination. For this purpose the changes in steady-state UV and visible fluorescence have been investigated and also time course measurements have been performed. In all cases the silica gel matrix proves to be a very suitable support for optical biosensing owing to its superior optical properties such as high transmittance, no alterations in fluorescence and absorption spectra of GOD after immobilization. When time course measurements are performed, the silica gel support allowed us to obtain larger linear calibration range and higher sensitivity. In addition a glucose optical biosensor has been developed and characterized using as catalytic element GOD immobilised onto a disk of gel properly bounded to a bundle of optical fibres.