Surface-enhanced Raman Spectroscopy Technology Based On Gold Magnetic Nano-substrates For Rapid Detection Of Aflatoxin

Aflatoxins,one of the most toxin nature cancerogen,lead a terrible threat to human health,environment and food economy.Aflatoxin B₁（AFB₁）is served as carcinogen?by International Agency for Research on Cancer（IARC）.Traditional methods to detect AFB1 include thin-layer chromatography（TLC）,high performance liquid chromatography（HPLC）,enzyme-linked immunosorbent assay（ELISA）and so on which were skilled technician requirement and time-consuming.And ELISA may yieldf false-positive results.Surface enhanced Raman spectroscopy（SERS）is a fast,convenient,and highly sensitive detection technique.SERS active substrates with high sensitivity is the key factor to increase SERS detection sensitivity.In this thesis,gold nanoparicles and gold magnetic nanoparticles were reacted with antiAFB₁ to prepare inmmune gold Raman substrate.And aflatoxin B₁ was rapidly detected by SERS technology.The primary aspects are as follows:（1）Gold nanoparticles were prepared based on Frens method.The influence of particle size on SERS effect was investigated and bset average paticle size was determined as 51.3 nm.This gold nanopaticles and rhodamine B isothiocyanate were reacted with antiAFB₁ to constract inmmune gold Raman substrate（Au-antiAFB₁）and Raman inmmune probe（RhB-antiAFB1）.Then AFB1 antigen was captured to form sandwich inmmune complex and AFB₁ was detected rapidly using Raman spectrometer.The lowest detection limit was 10.0 ng/mL.Linear range of detection was 10.0 ng/mL¹.0×10³ ng/mL.The recovery rate of samples was in the range of81.62%⁹2.48%and the relative standard deviation was 2.41%⁶.06%.The detection time of single sample was less than 20 min.（2）Gold nanoparticles was prepared through silane-reduction.Fe₃O₄nanoparticles,as a magnetic core,were first surface modified and Au nanoparticles were assembled on the surface of Fe₃O₄/SiO₂ to prepare Fe₃O₄/SiO₂/Au.This gold magnetic nanopaticles and rhodamine B isothiocyanate were reacted with antiAFB₁to constract inmmune gold magnetic Raman substrate（Au-antiAFB₁）and Raman inmmune probe（RhB-antiAFB₁）.Then AFB₁ antigen was captured to form sandwich inmmune complex and AFB₁ was detected rapidly using Raman spectrometer.The lowest detection limit was 5.0 ng/mL.Linear range of detection was 5.0 ng/mL⁵.0×10² ng/mL.The recovery rate of samples was in the range of81.62%⁹2.48%and the relative standard deviation was 1.80%⁶.78%.The detection time of single sample was less than 10 min.