| The biosensors which are cross-region and multi-subject advanced diagnosis instruments. The biosensors can satisfy the needs of people in clinical detection, environmental monitoring and biochemical analyzing, etc. In this experiment, BSA and chitosan are taken as cross-linking reagents, and nanoparticles gel and uricase are cross-linked on egg membrane. The three electrode system which composed of two platinum electrodes and saturated calomel electrode, act as working electrode, counter electrode and reference electrode respectively, and execute uricase biosensor. Make the enzyme film adhibit onto working electrode tightly. Then we execute the uricase biosensor. When the uric acid of the body passes the enzyme film, it is detected the reaction electric current here, then converted this current and displayed the concentration of uric acid. The application of uricase biosensor detecting concentration of uric acid of the body blood and urine, is a kind of accurate, fast and simple method. It can help to detect the diseases, such as nephropathy, leukemia and tumor etc. The choice of electrode, concentration of uricase and nanoparticles, temperature, pH value of solution and scan rate are studied emphatically. The 1U uricase in pH 6.50 solution at the temperature 45 ℃ are appropriate conditions, and the scan rate is 60 mV/s. The linear range of the biosensor is 1.0×10-51.0×10-3 mol/L, the detection limit of the biosensor is 5.0×10-6 mol/L,RSD is 3.70%(n=10). Using ammonia as catalyst and hydrolysis of tetraethylorthosilicate(TEOS), the microemulsion system which are made of TritonX-10, octanol, cyclohexane and ammonia are studied in this paper. The effect of the preparation of nano-silicon is characterized by TEM. The analyzing results show that the nano-silicon particles are round particles, and the diameter of silica by this preparation method is about 80nm. In this study, the nano-silicon is modified via the following method. Amino groups as an initiator site, the silica surface is achieved by the treatment of silica with γ-aminopropyltriethoxysilane. Dendrimer is propagated from silica surface by repeating two processes: Michael and amidation of the resulting esters with ethylenediamine. The effect of the surface modification of silicon dioxide is characterized by the FTIR, TG, acid-basetitration, etc. The percentage of grafting increases with increasing generation. |
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