Patent ID: 7754278

Claim:
A method for preparing magnetic polymer microbeads, comprising the following steps: (a) preparing polymer particles, and immersing the polymer particles into a solution in order to swell the polymer particles, wherein the polymer particles are made of polystyrene, or a copolymer including styrene as monomer, and the solution includes a medium polar solvent which allow the polymer particles to swell, but not to be dissolved therein, and allow the polymer particles to be evenly dispersed; (b) adding magnetic nanoparticles to the solution and allowing the magnetic nanoparticles to enter an interior of the polymer particles; and (c) separating the polymer particles from the solution, wherein the polymer particles are non-porous, or the pore size of the polymer particles is smaller than the particle diameter of the magnetic nanoparticles before swelling the polymer particles, and the magnetic nanoparticles can enter an interior of the polymer particles by molecular diffusion after swelling the polymer particles.