Study On Glucose Nanobiosensors

Diabetes mellitus is a common and frequently-occurring disease, which seriously menaces the healthy of the human beings. Therefore, the diagnosis and treatment of diabetes mellitus is a heavy responsibility for the biomedical engineering field of the world. Diabetes has been attracted high attention of world, and the number of diabetes sufferers increased gradually in recent years. How to detect and inspect diabetes effectively is a very important question all the while.Electrochemical glucose biosensors are the major technique for blood glucose analyses in clinical practice, for the advantages of glucose biosensors are obvious: high specificity, rapid response, simplicity and low cost of analysis, etc. At present, glucose biosensors have shortcomings: big consume of glucose oxidase and complicated techniques. Therefore, it is very essential to explore new materials and methods for preparation of glucose biosensor with high response.In this paper, we used different nano-materials to modify carbon paste electrodes, and designed disposable electrochemical glucose biosensors for detection of an analysis blood glucose, which in a liquid sample is formed with a working electrode and a reference electrode disposed within a sample-receiving cavity and a reagent layer disposed within the sample-receiving cavity and over the working electrode. The reagent layer contains at least glucose oxidase and a sort of interferant for producing an electrochemical signal in the presence of the analysis.When electrochemical detective system in microfluidic analytic system is applied in fluid-flowing small samples testing, the testing results are not stable, because of the influence of microreactors' channel height on diffusion kinetics. So through the analysis of hydrokinetics and diffusion kinetics, the minimum diffused layer's thickness of coplanar electrodes in unstable state diffusion process of immobile liquid is deduced. Based on it, a design concept of microreactors' channel high matching to electrode kinetic process main in diffusion is proposed, electrodes and microreactors are completed, and the feasibility of this design concept is validated by experiments.Then, we designed three glucose biosensors modified by CB-g-PSS, cabon nanotubes and nano-SiO₂ respectively.Poly (sodium 4-styrenesulfonate) (PSS) was grafted onto carbon black surface by ambient surface-initiated atom radical transfer polymerization. Different effects were achieved by different method to modify biological sensitive film of glucose biosensors. The experiments indicate that the sensitivity of deposed by CB-g-PSS is 2 times of no modified. Through analyzing the mechanism of electrodes modified by CB-g-PSS by different methods, the results reveal that conductivity and nano property of CB-g-PSS benefit to immobilize enzyme, improving kinetic process of enzymatic reaction and increasing the sensitivity of biosensors. And then, we introduced carbon nanotubes into glucose biosensor to improve the capability of biosenor. The experiments indicate that the sensitivity of deposed by carbon nanotubes is 4 times of no modified. Testing of different concentration glucose: RSD<15%.We designed a polymer- nanoparticle blood glucose biosensor. We accomplished the designing and experimental work about the biosensor and finish all the clinical experiments with satisfactory results. K₃(FeCN₆) acted as electron transport reagent, and glucose oxidase was immobilized in the multiple membrane matrix consisting of polymer and hyrophilic nano-SiO₂ on screen-printed carbon paste electrodes. In this way a glucose biosensor modified by hydrophilic nano-SiO₂ and polymer was completed. The experiment results turned out that the membrane of nano-SiO₂ doping had a good hydration, nano-SiO₂ could catalyse redox reaction, and kinetic process of enzymatic reaction was improved greatly. The experiments indicate that the sensitivity of modified by nano-SiO₂ is 2.6 times of no modified. Testing of different concentration blood glucose: RSD<3.5%. And the linear range of glucose biosensor was increased to 1.1～33.3 mM. So it has highly applied value. We discussed detailedly about how to design the biosensor and how to confirm their working parameters in this paper.At last, according EIS of blood glucose nanobiosensors, equivalent circuit and mathematical model were built. Kinetic parameters were calculated. Mechanism of blood glucose nanobiosensors was analyzed deeply.