The invention discloses a preparation method of
sandwich type immunomagnetic beads with high
thermal stability, which comprises the following steps: by taking
polystyrene microspheres as a template, introducing oil-phase Fe3O4 nanoparticles into the
polystyrene microspheres through a swelling method, and then carrying out hydrolytic
condensation reaction on the surface of a
microsphere assembly by utilizing n-octyltrimethoxysilane OTMS to obtain the
sandwich type immunomagnetic beads with high
thermal stability. The preparation method comprises the following steps: carrying out surface
amination modification on a
silicon dioxide
thin layer which is grown by
hydrolysis of tetraethoxysilane TEOS to realize
coating of an outermost organic shell layer, carrying out surface
amination modification, and carrying out cross-linking on 1, 4-
butanediol diglycidyl ether and
erythritol on the surface to form an
epoxy polymer layer so as to obtain the sandwich-type
immunomagnetic bead with a cross-linked
epoxy polymer layer introduced to the outer layer. According to the
epoxy group modification process on the surface of the
magnetic bead, a direct cross-linking modification process is adopted, so that the operation steps are simplified, and the obtained epoxy group
magnetic bead is ensured to show excellent
biocompatibility. In addition, the method omits the tedious process of functional group activation, and allows
direct coupling with the
antibody, thereby greatly improving the efficiency and convenience of the experiment.