Preparation of surface plasmon resonance biosensor based on magnetic core shell Fe_3O_4SiO_2 and Fe_3O_4Ag SiO_2 nanoparticles

摘要

In this paper, surface plasmon resonance biosensors based on magnetic core/shell Fe_3O_4/SiO_2 and Fe_3O_4/Ag/SiO_2 nanoparticles were developed for immunoassay. With Fe_3O_4 and Fe_3O_4/Ag nanoparticles being used as seeding materials, Fe_3O_4/SiO_2 and Fe_3O_4/Ag/SiO_2 nanoparticles were formed by hydrolysis of tetraethyl orthosilicate. The aldehyde group functionalized magnetic nanoparticles provide organic functionality for bioconjugation. The products were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), FTIR and UV-vis absorption spectrometry. The magnetic nanoparticles possess the unique superparamagnetism property, exceptional optical properties and good compatibilities, and could be used as immobilization matrix for goat anti-rabbit IgG. The magnetic nanoparticles can be easily immobilized on the surface of SPR biosensor chip by a magnetic pillar. The effects of Fe_3O_4/SiO_2 and Fe_3O_4/Ag/SiO_2 nanoparticles on the sensitivity of SPR biosensors were also investigated. As a result, the SPR biosensors based on Fe_3O_4/SiO_2 nanoparticles and Fe_3O_4/Ag/SiO_2 nanoparticles exhibit a response for rabbit IgG in the concentration range of 1.25-20.00μgml-1 and 0.30-20.00μgml-1, respectively.