Preparation Of Metal Oxide Nanostructures And Their Application In Biosensors

Biosensors have broad application prospects in biological, basic research, food analysis, clinical medicine and diagnosis, environmental monitoring, process control and detection and other field. A lot of metal oxide nanostructures which have special physical and chemical properties, can be used as an ideal material for biosensor. So we synthesized metal oxide nanostructures with different materials and microstructures through chemical vapor deposition method, and studied the performance of the biosensors based on these products. The Main study contents and innovations are as follows:1. Using zinc powder as materials, we synthesized the tetrapod ZnO nanostructures by a chemical vapor deposition method. The morphology and dimension of the product was examined by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM). Then through a coating method, GC/ZnO/HRP/nafion and Au/ZnO/GOD/nafion composite electrode were prepared and studied. Investigation results demonstrated that biosensors based on tetrapod ZnO nanostructures showed a response to H2O2and glucose with high sensitivity. In order to increase its response to H2O2, we added the electronic media hydroquinone in the phosphate buffer. As a result, the sensitivity of the sensor had been improved significantly. This result proved that the tetrapod ZnO nanostructures were ideal materials to building biosensors. At the same time, the preparation method was also applicable to biosensors with other enzyme systems, showing good application prospects.2. Using mixed powders of Zn and Mg with mass ratio of10:1. we fabricated novel MgO/ZnO composite nanosheets by a simple chemical vapor deposition method. Their morphology, size, composition and growth mechanism were also studied. Then through a coating method, the Au/nanosheets/HRP/nafion and Au/nanosheets/GOD/nafion composite electrode were prepared. Investigation results showed that the sensor had high sensitivity without electronic media. Although the electrical conductivity of pure MgO was bad, the small quantity of ZnO in the composite nanosheets can enhance the direct electron transfer of horseradish peroxidase immobilized on the materials effectively.3. Finally, we synthesized Ga2O3nanowires using the same preparation method and constructed a Ga2O3biosensor through a coating method (Au/Ga2O3/HRP/nafion composite electrode). It is found that the modified electrode has good catalytic effect, indicating that Ga2O3has good electron transfer ability. Our study showed that Ga2O3nanomaterials can also be used as an ideal material to building biosensors.