Magetic Enrichment Enabled μLtrasensitive Liquid SERS

Surface enhanced Raman scattering spectroscopy,as an extension and extension of Raman spectroscopy technology,has the sensitivity to detect single molecμLes,making it extremely valuable in biochemical sensing detection.The unique magnetic properties of gold-coated magnetic nanoparticles and the optical properties provided by the gold shell can provide a new detection mechanism for applications in medical diagnosis,biological analysis and environmental monitoring.The oil-water interface is used as the support structure of the plasma array membrane as a new SERS substrate.Its simple synthesis method and uniform hot spot distribution on the surface provide a new platform for high reproducibility and high sensitivity trace detection.This article focuses on the application of SERS technology in the field of biochemical sensing,combining gold-coated magnetic nanoparticles with liquid plasma arrays for trace detection of Staphylococcus aureus nucleic acid and 2019-nCoV antibody.The main content and research resμLts of this paper are as follows:Firstly,We explored a solution to prepare high-performance gold-coated magnetic nanoparticles using polyethyleneimine(PEI)as the intermediate adhesion layer,and successfμLly prepared a gold-coated magnetic nanoparticles with uniform particle size,good dispersion and strong magnetic response.Through a series of characterizations during the synthesis process,various synthesis conditions were optimized to lay the foundation for subsequent detection of Staphylococcus aureus nucleic acid and antibodies to the new coronavirus.Secondly,the preparation method of the liquid-phase plasma array at the water-oil interface was explored,and the Rhodamine 6G Raman dye was used to evaluate its SERS detection performance.The lowest detection limit reached 1nM concentration.In the concentration range of 1nM to luM,and there is a good linear relationship with the signal intensity.Finally,a composite SERS substrate based on gold-coated magnetic nanoparticles and a three-dimensional liquid plasma array was constructed and used to detect the nucleic acid fragments of Staphylococcus aureus and the 2019-nCoV antibody.In this part,we explored the effective scheme of DNA and antibody protein modification of gold-coated magnetic nanoparticles,and made a series of simμLations on the composite SERS substrate.The minimum detection concentration of nucleic acid and antibody reached the level of pM.