The Detection Of Carcinoembryonic Antigen Based On The PRRS Properties Of A Single Silver-coated Gold Nanostar

As a new technology of spectrum analysis, localized surface plasmon of single particle technology has been well applied in biology, chemistry and medicine, mainly attributing to its characteristics of high sensitivity, stability, noninvasive detection.It can exhibit unique optical absorption and scattering properties, combined with a dark field microscope can be obtained resonance Rayleigh scattering spectra of individual nanoparticles (PRRS) properties. various metal nanostructures with LSPR activity have been synthesized, such as nanorod, nanowire, nanostar, nanoshell. Au-Ag Bimetallic Nanoparticle. etc. Taking advantages of the higher LSPR activity of silver and the homogeneous superiority of gold, researchers have synthesized multieompoent architectures, such as Au@Ag NSs, Au@Ag shells, and Au@Ag nanocages, Which PRRS spectrum has stronger sensitivity to the environment SERS enhancement effect, stability and biocompatibility. The most critical aspect of performing the PRRS-based immunoassay is fabrication of PRRS sensor. In our work, the novel monodispersed silver-coated gold nanostars (AuNSs@Ag) were synthesized as enrichment substrates. Based the immunoassay strategy, CEA in the level of 1 pg/mL-10 ?g/mL have been detected.The details are as follows:1. Preparation and characterization of silver-coated gold nanostars(AuNSs@Ag)A novel monodispersed silver-coated gold nanostars(AuNSs@Ag) are fabricated by seed-mediated methods and chemical reduction methods. Firstly, Based on a seed-mediated growth approach, gold nanostars with uniform size and shape have been prepared.secondly, silver-coated gold nanostars(AuNSs@Ag) were synthesized based on chemical reduction methods. By chemical reduction method, AgNO3 were reducted in the surface of the gold star, by controlling the concentration of AgNO3, We successfully formed silver-coated gold nanostars(AuNSs@Ag)(90± 5nm)with a uniform size and shape.Finally,bidirectional characterized the surface appearance and the optical properties of silver-coated gold nanostars(AuNSs@Ag) by scanning electron microscopy, transmission electron microscopy,UV spectrophotometer,single-particle spectrometer.The results show that the silver-coated gold nanostars(AuNSs@Ag) with structural stability,uniform size and has good resonance rayleigh scattering spectra properties.2. Fabrication of silver-coated gold nanostars (AuNSs@Ag) resonance rayleigh scattering interfaceA novel monodispersed silver-coated gold nanostars (AuNSs@Ag) resonance rayleigh scattering interface were fabricated, and assessed its PRRS properties. Firstly,silver-coated gold nanostars,which the absorption spectrum peak at an absorbance 1 were diluted different times,randomly immobilized onto the prepared APTES,obtained DFM image with Dark-field microscope.then, Using software ImageJ to calculate the number of particles, Using the concentration gradient method to prove a single particle.finally, selected the appropriate concentration to prepare a monodispersed resonance rayleigh scattering interface. And measuring the resonance rayleigh scattering properties of the material in a different environment (air,water, ethanol, a mixture of ethanol and glycerol, pure glycerol), the results show the high sensitivity of the material environment.3. Detection of CEA based on silver-coated gold nanostars (AuNSs@Ag) PRRS immuno -sensorAccording to the above work of controllable synthesis of silver-coated gold nanostars (AuNSs@Ag)and their resonance rayleigh scattering characteristics, we fabricated PRRS immuno-sensor for CEA based on AuNSs@Ag and resonance Rayleigh scattering interface, a thiol derivative 4-mercaptobenzoic acid (4-MBA) and CEA labeled antibody was utilized to functionalize the particle surface before being chemically capped with the CEA. Finally,By antigen-antibody binding,to achieve the carcinoembryonic antigen identification and quantitative analysis.The results show that a very good linear response in the lower concentration range between detection concentration and resonance Rayleigh scattering wavelength shift, showing strong potential for the clinical diagnosis of cancer biomarkers.