Research On Construction And Application Of Magnetic SERS Sensor

Surface enhanced raman scattering（SERS）technology overcomes the defects of Raman scattering.It has the advantages of trace,non-destructive,rapid and fingerprint identification.It has attracted much attention in the fields of biological analysis,medical examination,food safety detection and environmental monitoring.Based on the advantages of SERS,combined with the selective recognition function of molecular imprinting technology and immune response and the characteristics of easy separation and enrichment of magnetic nanoparticles.A number of magnetic SERS sensors were constructed and successfully applied to the detection of actual samples.The specific research contents include the following aspects:1.Take Fe₃O₄@SiO₂@Ag as the matrix material,3-aminopropyltriethoxysilane（APTES）as the functional monomer,tetraethyl silicate（TEOS）as the crosslinking agent,and ammonia（NH₃·H₂O）as the The initiator and ofloxacin（OFX）were used as template moleculestopreparemagnetic molecularly imprintedpolymers Fe₃O₄@SiO₂@Ag-OFX-MIPs,and they were successfully used in the quantitative detection of OFX.The introduction of an external magnetic field enables the rapid separation of MIPs from the sample solution,shortens the detection time,enriches the target molecules,and further enhances the Raman signal.This method has high sensitivity,strong selectivity and good reproducibility.The standard addition test of ofloxacin eye drops on the market,the recovery rate is between 96.9%and 106.9%,and the RSD is less than 1.71%.2.Based on the self-polymerization effect of dopamine,using magnetic PDA NPs as the substrate,dopamine（DA）as the functional monomer,and AFP@4-MPBA as the template molecule,a SERS-based magnetic PDA molecularly imprinted sensor was developed for use in humans.For the quantitative detection of alpha-fetoprotein in serum,the detection limit can reach 1.0 ng/m L.The sensor shows high sensitivity,good selectivity,reproducibility and uniformity of Raman signal.Through the addition test of AFP in human serum,the recovery rate is between 93.9%and 106.1%,and the RSD is≤2.86%.3.Based on the specific recognition of antigen and antibody,the high sensitivity of SERS and the separation and enrichment of magnetic particles,the boron affinity magnetic immune SERS sensor was successfully constructed and applied to the specific recognition and detection of AFP in human serum.The sensor has good selectivity,wide linear range（1.0 ng/m L～1.0 mg/m L）and high sensitivity（1.0 ng/m L）.Through the spike test of AFP in human serum,the recovery rate is between 85.8%～105.7%,and the RSD is≤3.52%.The sensor can realize the specific detection of different antigens by changing the surface-modified antibodies,and has certain applicability.Therefore,this method can provide a new idea for clinical detection of antigen or antibody,and has good application value in the early diagnosis of various diseases.