Glucose Biosensor Based On Glucose Oxidase Immobilized On A Swim Bladder Membrane

The technology of enzymatic immobilization included absorption, entrapment, covalent binding and cross-linking methods. Various materials can be used as enzymatic immobilization carrier, such as gel, inorganic materials, synthetically organic polymer, biomaterials and so on. It was research in the technology of enzymatic immobilization and the materials for immobilizing enzyme. By compared with various biomaterials, it was the first time to use swim-bladder membrane as the support for immobilizing glucose oxidase. The tissue of swim bladder membrane provided a perfect micro-environment for glucose oxidase, and adapted to immobilized enzyme.The glutataldehyde solution was as cross-linking agent. The enzyme-immobilized swim-bladder membrane was placed on the surface of an oxygen-sensitive optode membrane. The oxygen-sensitive membrane was constructed from tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(Ⅱ) ditetrakis (4-chlorophenyl) borate adsorbed on silical gel particles. This Ru(Ⅱ) polymer was collected an fluorescence emission intensity at 605 nm, when the excitation wavelength was set at 470 nm, and the fluorescence intensity can be quenched when the Ru(Ⅱ) polymer molecules reacted with oxygen molecules. The glucose biosensor was built by positioning both enzyme-immobilized swim-bladder membrane and oxygen-sensitive optode membrane in a laboratory-made flow cell.The detection scheme was based on the depletion of dissolved oxygen content upon exposure to glucose solution and the change in fluorescence intensity of the oxygen-sensitive membrane was monitored and related to the glucose concentration. It was found that the optical glucose biosensor had a sensitive response. At 20°C , the linear range of the concentration of glucose was 0.100— 0.800 mmol L1, and the linear range of the concentration of glucose was 0.010— 0.400 mmol L''at 30°C. It was also studied the effect of pH, phosphate buffer concentration, temperature on the glucose biosensor in detail. The glucose biosensor demonstrated a perfect repeatability and selectivity, and the RSD of the repeatability test was 2.1 %. In 4°C, the glucose biosensor can be kept for 10 months. It has been successfully applied to the determination of glucose content in human blood serum and urine sample.