Preparation Of Biocompatible Nonocomposites And Their Applications In Biosensor

Because of good selectivity, high sensitivity, simple operation and real time on-line monitoring, biosensor has become a cutting-edge subject in modern analytical chemistry and life science, which also plays an important role in clinical diagnotic, food industry and environmental monitoring and so on. Preparation of a proper enzyme carrier is crucial for the good performance of biosensors. In this work, we prepared biocompatible nanocomposites and explored their applications in glucose sensor and immunosensor. The main research content and results are show as below:1. Enzymatic glucose sensor was fabricated based on PMMA-BSA-GNPs biocompatible nanocomposites. First we prepared PMMA-BSA core/shell nanoparticles,and after combining them with gold nanoparticles(GNPs), we obtained a biocompatible supporting material for GOx, which was proved to be excellent materials used in enzymatic glucose sensor. In this part, we also explored the performance differences between two types of glucose sensors when PMMA-BSA core/shell combined with GNPs and GNPs(situ), respectively. And we explored the enzyme carrier traits as well when replaced GNPs with PNPs to combine with PMMA-BSA. The results showed that enzymatic glucose sensor modified by PMMA-BSA-GNPs exhibited excellent performance toward glucose. Two linear ranges of 0.99-9.09 m M and 9.09-13.79 m M were obtained with sensitivities of 18.68 μAm M-1cm-2 and 10.24 μAm M-1cm-2, respectively. This glucose had a long stability even in room temperature. Results also showed that GNPs(situ) modified enzymatic glucose sensor had a more sensitivity and current response than modified by GNPs, and PNPs modified gluoce sensor had a much more excellent performance than that modified by GNPs in terms of current response and sensitivity due to its catalytic property for dissociation of H2O2.2. Nonenzymatic glucose sensor was fabricated based on Fe3O4-PEI-GNPs magnetic composited nanoparticles. Firstly Fe3O4 nanoparticles were obtained via co-preciptation method, and then branched polyethylenimine(PEI) wae wraped on the surface of these particles to get amino-carried Fe3O4-PEI nanoparticles. Afterwards, GNPs were absorbed on the surface of such composited nanoparticles through electrostatic attraction to get nanocomposites Fe3O4-PEI-GNPs. Since GNPs have elctrocatalysis toward glucose, the resulted material has an ability to apply in nonenzymatic glucose sensor. When modified glass carbon electrode with Fe3O4-PEI-GNPs nanoparticles based on GCE, the resulted nonenzymatic glucose exhibited a good liner range of 3.84-17.35 m M toward glucose with sensitivity of 126.13 μAm M-1cm-2.3. Label-free immunosensor was fabricated based on PMMA-BSA-Fc biocompatible composited nanoparticles. By reacting PMMA-BSA particles with ferrocenecarbaldehyde(Fc), we got a functionized material of PMMA-BSA-Fc with electrochemical activity. When modified gold electode(Au) with this material and followed by absorbing GNPs and soaking in BSA to block possible remaining active sites, we obtained a lable-free immunosensor: Au/PMMA-BSA-Fc-GNPs-anti CEA. The results showed that this immusensor had linear range of 5-160 ng/m L with dection limit of 0.18 ng/m L.