Design And Fabrication Of Complex Structure Sers Substrate And Its Application In Analytical Detection

Surface-enhanced Raman scattering?SERS?is a vibrational spectroscopy with molecular fingerprint specificity and single molecule sensitivity.As a powerful analytical tool,SERS possesses a lot of advantages,such as simple and rapid operation,high spectral resolution,narrow peak and simultaneous detection of multiple components,allowing its widely application in the fields of analytical chemistry and life sciences.In recent years,to expand the application of SERS technology in the field of analytical chemistry and promote the development of SERS analysis technique,much focus has been placed on the preparation of functionalized SERS substrate with high sensitivity,good stability and excellent reproducibility.In this paper,we have designed and prepared the SERS active substrate and nanotags with complex nanostructure.Using the elements with functional modification,the strategies for highly sensitive and selective detection of metal ions and cancer biomarkers have been developed.The main contents are as follows:1.Preparation of sea urchin TiO₂@AgNPs SERS substrate and its application for trace detection of Cr???.The TiO₂@AgNPs composite microsphere with hollow sea urchin structure was prepared by chemical template method.Base on the "signal amplification",using TiO₂@AgNPs modified by glutathione?GSH?with 2-mercaptopyridine?2-MPy?as a Raman reporter,the combination of Cr???with GSH would induce the aggregation of nanoparticles and produce a large number of SERS "hot spots",leading to the ultra-sensitive detection of Cr???.In addition,the photocatalytic properties of TiO₂@AgNPs would beneficial for the recycle of SERS substrate,which is of great significance for the practical application of SERS.2.Preparation of Au-RNNPs SERS nanoprobe and its application for multiple miRNAs detection.The Raman reporter molecules encoded Au-RNNPs with very narrow nanogap and rough surface were synthesized by DNA-mediated.Based on the modication of detection probe for identifying the target miRNAs on the surface of Au-RNNPs,SERS nanoprobe was fabricated.In addition,using bacteria as templates,we realized the green synthesis of micro-sized hollow silver microspheres?Ag-HMSs?with high specific surface area and SERS activity.With the modification of capture probe on the surface of Ag-HMSs,the SERS capture substrate for target miRNAs was constructed.The highly sensitive and specific SERS detection of single and multiple miRNA biomarkers relevant hepatocellular carcinoma has been completed via sandwich-like hybridization.