The Noble Metal Composite Nanoparticles Construction And Biosensing Application

Multi-component noble metal plasmonic nanosuperstructures have better local plasmonic properties,surface-enhanced Raman scattering（SERS）properties and metal-enhanced fluorescence properties than single-component noble metal nanoparticles,and their compositional and morphological diversity can enhance their application in numerous fields.It has been demonstrated that multi-component noble metal plasmonic nanoparticles can be combined with magnetic nanoparticles and up-conversion luminescent materials in order to construct a high-sensitivity biomolecule monitoring nanosensor based on noble metal superstructures.Also,modification can enhance the specific recognition function,allowing complex matrixes to be enrichment,separated,identified,and output multi-signals as well as reducing the problems associated with poor selectivity,low accuracy,and easy interference.Therefore,this thesis focuses on researching the construction of optical analytical platforms based on noble metal superstructured nanoparticles to detect biomolecules,perform rapid and accurate clinical sample analysis,and expand the biological applications of multicomponent noble metal plasma superstructured nanoprobes.Specifically,this thesis addresses the following research efforts.1.Ultrasensitive Sandwich-Type SERS Biosensor Based on Dual Plasmonic Superstructure for Detection of Tacrolimus in Patients.Using Fe₃O₄@Si O₂@Ag flowers and Ag@Au sandwich superstructures,a rapid and effective SERS sensor for the detection of FK506 has been constructed.A large specific surface area was found for the Fe₃O₄@Si O₂@Ag flowers.Consequently,there are a number of interparticle hot spots,giving it an advantage in detecting SERS.As a result of a coupling of anti-FK506 antibodies to the surface of the cell,they show high specificity and sensitivity to SERS signals against FK506.Furthermore,in order to maximize SERS signal amplification,the antibody Ig M-modified Ag@Au plasmonic superstructure can be used to target FK506,forming a sandwich structure of plasma superstructure-target-plasmonic superstructure（Fe₃O₄@Si O₂@Ag flowers-Anti FK506-FK506-Ig M-Ag@Au）.Optimally,the probe can detect FK506 at concentrations ranging from 0.5-20 ng/m L,with a minimum detection limit of 0.33ng/m L.Additionally,the sensor can be used to analyse the detection of FK506concentrations in transplant patients’blood.There is a high degree of agreement between these results and clinical outcomes.The sandwich-type probe used in this study offers an innovative potential biosensor technique for the detection of FK506,which is expected to be used in clinical diagnostic procedures.2.Dual-Signal Ratio Colorimetric Sensor Based on AuNRs@UCNPs Superstructure Nanoprobe for Hypochlorite Acid Detection.Based on AuNRs@UCNPs superstructure,a ratiometric colorimetric fluorescence dual-signal sensor was constructed to detect Cl O^-rapidly and accurately.UCNPs and AuNRs were adsorbing electrostatically on each other.UCNPs fluorescence peak at650 nm was burst at 980 nm due to energy transfer caused by spectral overlap.The spectral overlap between AuNRs and UCNPs changes as the AuNRs are gradually etched by Cl O^-along the longitudinal direction,resulting in a gradual recovery of fluorescence intensity at 650 nm as well as a gradual suppression of fluorescence peak at 540 nm.Consequently,the ratiometric fluorescence signal at 650 nm/540 nm correlates positively with the concentration of Cl O^-.The rich colour change during the etching of AuNRs allows the sensor to function as a ratiometric fluorescence sensor as well as a colorimetric sensor for the detection of Cl O^-.As a result,the prepared AuNRs@UCNPs ratiometric and colorimetric fluorescence dual-signal sensor provides a promising method for the detection of ClO^-.