Preparation And Modification Of Gold Nanostars And Application In SERS Detection

Surface-enhanced Raman scattering?SERS?spectroscopy has evolved into one of the important analytical techniques in the scientific community for highly sensitive and selective detection of target molecules.Among all kinds of plasmon nanomaterials that can be used in SERS,gold nanostars with special tip branching structure attract great interest due to their unique local surface plasmon resonance?LSPR?optical properties and corresponding local field enhancement effects.The LSPR of gold nanostars can produce tunable plasmon peaks from visible to near-infrared region by adjusting the shape and branch length,and has good photothermal conversion effect.Combined with platinum particles,its synergistic effect will show greater advantages in enhancing the surface electromagnetic field and catalytic performance,and realize the versatility of nanomaterials.Based on the above discussion,how to prepare LSPR tunable nanoparticles and use the multifunctionality of the material to establish a dual-channel colorimetric and SERS dual-channel sensor for molecular detection.The following research contents are proposed:?1?Gold nanostars?Au NSs?were synthesized by a surfactant-free method.The effects of three reagents on the LSPR band during the reaction are studied.It is found that AgNO₃ can effectively adjust the morphology and size to make the local plasmon resonance mode of the particles in the visible-near infrared region tunable.The effects of the morphology of Au NSs on the photothermal effect and SERS activity are discussed in detail.As the tip length and sharpness increase,the photothermal effect and SERS performance increase.Au NSs with the highest SERS activity are selected for SERS detection substrates,and the sensitive detection of the pesticide thiram is achieved.?2?We used the seed growth method to deposit platinum particles on the surface of gold nanostars to successfully prepare gold-platinum nanostars?Au@Pt NSs?.Au@Pt NSs have high peroxidase activity and SERS characteristics by adjusting platinum content.The catalytic properties of Au@Pt NSs lead to the rapid oxidation reaction of the colorless substrate TMB under the H₂O₂-mediated conversion and turn blue.The oxidation product oxTMB can be effectively and accurately identified by SERS spectroscopy,thereby enabling in situ monitoring of the catalytic reaction of Au@Pt NSs.A colorimetric and SERS dual detection sensor for detecting hydrogen peroxide and glucose concentration is established,and the sensor is used for the actual detection of glucose in human serum.