Synthesis Of Botryoid-shaped Nanoparticles And Its Application In Food Safety Inspection

A kind of heterozygosis nanoparticles BSNPs consist of Ag and Au were prepared in this work, and several applications were did based on BSNPs.The research content of this paper can be summarized as the following aspects:1. The Au/Ag bimetallic nanostructure was synthesized by combining galvanic displacement reaction with seed-mediated metallic nanoparticle growth. In this preparation, the Ag nanoprisms-BSA was taken as the template, the chloroauric acid tetrahyrate as the oxidizing agent and the ascorbic acid as the reducing agent. It should be noted that the ratio of Au and Ag is an important factor during the preparation of BSNPs.2. Because of its huge specific surface area, the prepared BSNPs were used in indirect Enzyme-linked immunosorbent assay(ELISA) to build BSNPs-HRP-IgG ELISA probe. The prepared BSNPs could load more IgG-HRP, improving the ratio of HRP and IgG. As a result, the reaction signal was amplified and detection sensitivity was improved. The BSNPs-HRP-IgG ELISA probe was used to detect ochratoxin A(OTA), of which the 50% inhibiting concentration(IC50) of the BSNPs-based probe was 0.04 ng/mL, decreasing the IC50 of conventional ELISA probe(0.35 ng/mL) by more than 8 times.3. The prepared BSNPs were used to build GCNPs-HRP-Anti(PSA) ELISA probe, which was used in sandwich ELISA to detect prostate specific antigen(PSA). The limit of detection of(LOD) conventional ELISA for PSA is 1 ng/mL and the LOD of BSNPs based ELISA was 0.05 ng/mL, which indicated that the sensitivity was promoted by 20 times.4. The surface-enhanced Raman scattering(SERS) substrate via absorbing BSNPs on the silicon wafer was built. In this work, the silicon wafer with amino group before absorption was modified. The prepared substrate has a lot of advantages, such as respond to several excitation wavelength and has high reproducibility. This substrate can be used to detect thiram in apple peel via SERS, of which the LOD is 0.1 μg/mL. When the concentration of thiram ranges from 0.5 to 10 μg/mL,the Raman intensity at 1377 cm-1 will show good linear.