Construction And Application Of Templated Nanogold Composite Materials

With the development of science and technology, more and more materials are taken into research by scientists,from macro-materials to nano-materials, from a single material to composite materials. At the same time, the preparation of materials also changed a lot. As a new method, template has become more and more important in the detection field for the ability to synthesize composite materials with particular characters. In this paper we firstly synthesized composite materials based on gold nanoparticles, and then studied the application of the materials in the detection of R6G and Salmonella.The research focused on the 863 program in our lab carried out in this paper can be devided into three aspects:The first part is the construction of chemical resistance immunosensor based on the gold-multi-walled carbon nanotubes composites materials to the detection of Salmonella flagellin. Firstly, muti-functional processing of template-carbon nanotubes has been carried out to form a series of active sites. The functional steps are oxidation, thiolation and then the freshly synthesized Au nanoparticles with the dimension of 15nm were adhered to the active sites of multi-walled carbon nanotubes to prepare composite materials,we finally use this materials to prepare the immunoelectrode to achieve label-free detection of the Salmonella enteritidis. The results showed that the modified electrode has excellent electrical response to Salmonella and strong sensitivity. This stability electrode with better repeatability, provides a simple, economical, practical and efficient analysis and detection method.The second part is the preparation of immune-based electrochemical sensor based on Au-Carbon electrode and it's detection of flagellin of Salmonella. Thionine was used as electroactive materials and the PBS solution of the hydrogen peroxide was used as the test solution, HRP was used to fix the antibody of Salmonella enteritidis to the surface of the carbon based electrode to carry out the detection by Cylic Voltammetry. In this paper, our research mainly focused on the thionine concentration, the hydrogen peroxide concentration, the pH of the test solution, incubation time, and the scan rate to get a better experiment condition.The third part focuses on the study of surface enhanced Raman scatter (SERS) of DNA-templated positively-charged gold nanoparticles. Positively-charged ten-nanometer gold colloidal particles were prepared, and self-assembled to the negatively-charged phosphate groups of the long-chainλ-DNA molecules to form DNA-Au complexes network. This self-assembly resulted in the formation of the high-density nanogaps between the Au nanoparticles absorbed on the DNA molecules, which attributed to the significant enhancement of SERS signal of the Rhodamine 6G molecules. The ten-nanometer gold particles, which are poor at the SERS detection, produced a greatly increase in the SERS sensitivity of R6G detection after the assembly onto the DNA. This study may provide a simple and stable way to produce SERS substrates with a uniform, consistent, and strong SERS enhancement effect by the assembly of metal nanoparticles to DNA molecules.