Study On The Enzyme Biosensor And Its Application In Diabetes Diagnosis

The level of blood glucose is the most important mark during the process of diagnosis and therapy of diabetes. Although there are commercialized glucose sensors in the markets, their performance and fabricating technics need to be improved. For satisfying this demand, we developed a new type of glucose enzyme electrode, it is based on a screen-printed carbon electrode and the basic electrode is covered with polypyrrole film by electrochemical polymerization, at the same time glucose oxidase is immobilized in the film by electrovalent bond. The experimental results show that under optimal polymerized condition, the response current of the enzyme electrode reaches its maximum value. When the concentration of glucose is in the range of 0-30 mM, the response currents measured by this enzyme electrode have a good linear relationship with glucose concentration, and the sensitivity is 0.065 μA.mM~-1.Among the complications of diabetes, ketoacidosis is very harmful for diabetics. Moreover it is important to determine the concentration of blood ketones for early diabetes diagnosis, so the quantitative method for blood ketones determination is imminently required. We developed a commercialized blood ketones biosensor. The detection limit of this biosensor is 1.5mg.L~-1. When the concentration of beta-hydroxybutyrate is in the range of 1.5-550mg.L~-1, the response currents measured by this biosensor have a good linear relationship with beta-hydroxybutyrate concentration, and the sensitivity is 0.011μA.(mg.L~-1)~-1. Furthermore, it can work without pretreatment of blood samples and only 2 microlitre whole blood or serum is needed for one test. These features are significant for clinical use.