Novel fiber optic glucose biosensor based on fluorescence quenching

Abstract

A new fiber optic glucose biosensor based on oxygen fluorescence quenching using lock-in technology has been presented. Ruthenium(II) complex, Ru(bpy)3Cl2, were used as the fluorescence indicator and cellulose acetate(CA) were used as the matrix membrane to immobilize the indicator and GOD, and the optimal conditions for the preparation of CA membrane has been studied. For the immobilization of GOD to CA membrane, albumin of bovine serum(BSA) and glutaraldehyde(GA) were used through covalence—cross bonding process. The relationship between the concentration of glucose and the phase delay??? has been studied, the results show that ??? has good relationship within the range of 50mg/dl—500mg/dl and the response time is less than 30 sec. Several factors to influence the sensor such as pH of the medium, the additional membrane layers, the properties of CA membrane have also been studied. The results indicate that its best pH range is between pH6.0 and 7.0, and the thickness of the additional membrane layers on the sensor head will influence the response time greatly, that is, the response time is controlled by the speed of dispersion of the dissolved oxygen into the fluorescence dye layer.