Preparation Of Surface Molecular Implicated Polymers And SERS Application Reserach

Surface-enhanced Raman scattering?SERS?has been widely used in various fields of analysis and detection due to its advantages of high sensitivity and on-line detection.Because SERS relies on SERS active substrates,the traditional precious metal and precious metal complex substrates are unstable in chemical properties,poor biocompatibility and non-selectivity,which limits the application of SERS technology in biological field and real sample detection.The rise of molecular imprinting technology has brought good news for the development of SERS technology.The shortcomings of SERS technology are the advantages of molecular imprinting technology.Molecular imprinting technique was used to prepare imprinted polymers which can selectively adsorb ampicillin,oxacillin,p-mercaptobenzoic acid,immunoglobulin G and carcinoembryonic antigen.The imprinted polymers were analyzed by SERS.The main contents are as follows:1.Ampicillin?AMP?was used as a template molecule,MPS as a Silanylation reagents,Methacrylic acid?MAA?as a functional monomer,Ethylene Glycol Dimethacrylate?EGDMA?as a cross-linking and 2,2'-Azobis?2-methylpropionitrile??AIBN?as an initiator.AMP was prepared on the surface of silver microspheres.The Energy Dispersive Spectrometer?EDS?and Infrared Spectroscopy?IR?showed that AMP molecularly imprinted polymers were successfully prepared on the silver microspheres.X-ray diffraction?XRD?showed that the crystal shape of Ag microspheres did not change after coating molecularly imprinted polymers and scanning electron microscope?SEM?and ransmission Electron Microscope?TEM?showed that the Ag@MIPs microspheres were the core-shell structures with more uniform particle size.Using Ag@MIPs microspheres as substrate,the AMP solution was detected by laser confocal Raman spectrometer?excitation wavelength of 638nm?.The results show that Ag@MIPs has strong SERS effect,the enhancement factor can reach 3.79×10⁵,and the detection limit of AMP is 10^-88 mol/L.The linear fitting of the strength of AMP and Raman spectra showed a good linear relationship with R²=0.959.The competitive adsorption results of Ag@MIPs showed that Ag@MIPs had high selectivity to AMP.The results of these studies can be used for the rapid,sensitive and selective detection of AMP.2.In this paper,using the alkylating reagent 3-Aminopropyltriethoxysilane?APTES?as the functional monomer,the Oxacillin?OXA?as the template and the tetraethyl orthosilicate?TEOS?as the crosslinker,the core-shell Ag@MIPs microspheres were prepared by"one step method".The morphology and structure of Ag@MIPs was characterized by SEM?TEM?EDS?XRD and IR.The results showed that the prepared Ag@MIPs microspheres were core-shell structures with more uniform particle size.The adsorption properties of core-shell Ag@MIPs and Ag@NIPs were investigated by UV.The results showed that the core-shell Ag-MIPs had higher selective adsorption properties to OXA.The core-shell Ag@MIPs were used as the SERS substrate and the laser confocal Raman spectrometer?excitation wavelength 638nm?was used to detect the OXA and the competitive adsorption test.The results showed that the Raman signal of the OXA with the core-shell Ag@MIPs was significantly enhanced and the detection limit for the OXA was up to 10^-15mol/L.It was good linear relationship between the concentration of OXA and the peak intensity of Raman characteristics and R² was 0.975.The results of competitive adsorption test showed that the adsorption of Ag@MIPs to OXA was high.The above results can be used for the detection of OXA in SERS with high sensitivity and selectivity.3.In this paper,a preparation method of magnetic core-shell silver molecularly imprinted polymer?Fe3O4@SiO2@Ag-MIPs?is introduced.Firstly,Fe3O4 was synthesized by hydrothermal method and modified with SiO₂?Fe₃O₄@SiO₂?.Then Ag nanoparticles?Fe₃O₄@SiO₂@Ag?were deposited on the surface of Fe₃O₄@SiO₂@Ag by seed growth method.Finally,p-mercaptophenylboronic acid?4-MBA?Fe₃O₄@SiO₂@Ag-MIPs were synthesized on the surface of Fe₃O₄@SiO₂@Ag by molecular imprinting technology.The morphology and structure of the composite were characterized by SEM,TEM,EDS,XRD and IR.Characterization.SERS results showed that Fe₃O₄@SiO₂@Ag-MIPs exhibited excellent surface-enhanced Raman activity and sensitivity to 4-MBA(detection limit was 10^-11 mol/L).When the dispersion of Fe₃O₄@SiO₂@Ag-MIPs on glass sheets was investigated,it was found that the Raman enhancement signals of 4-MBA were almost identical at seven random points on glass sheets,indicating that the substrate had good dispersion.When the competitive adsorption of Fe₃O₄@SiO₂@Ag-MIPs was investigated,it was found that the base had high selectivity for 4-MBA.The above experimental results show that the preparation method of Fe₃O₄@SiO₂@Ag-MIPs substrate is simple,dispersible,sensitive and selective.It has potential ultra-sensitive sensing and is expected to be used in SERS detection of food and medicine.4.In this paper,a method for preparing biomimetic SERS sensor is introduced.It is used for the specific identification and detection of trace CEA in human serum.The method is established by specifically recognizing and capturing the target glycoprotein MIPS and SERS probe.Using 4-vinylphenylboronic acid?VPBA?as functional monomer,ethylene glycol dimethacrylate?EGDMA?as crosslinking agent,ethylene glycol?EG?and cyclohexanol as porogen,a polymer?VPBA-Co-EGDMA?capable of adsorbing glycoproteins was synthesized on the surface of 4-point array glass sheet.Then MIPs were synthesized by VPBA-Co-EGDMA which adsorbed target glycoproteins on the fixed surface of dopamine hydrochloride?DA?.The target glycoprotein captured by probe labeling is to construct a sandwich structure complex of"MIPs-target glycoprotein-SERS probe".The biomimetic SERS sensor presented in this paper shows excellent selectivity and high sensitivity for CEA detection?detection limit can reach 0.1ng/mL?,and it is easy to modify template glycoprotein for specific adsorption and detection of other glycoproteins.This is expected to become a new strategy for clinical non-immunoassay of CEA.