US Patent 7282540 Process for producing particles for diagnostic reagent

A process of producing particles for diagnostic reagent, including forming a matrix particle by mixing a nuclear particle having a CV value of 20% or less and a magnetic substance containing at least one of Fe2O3 and Fe3O4 and giving a shear force to the mixture to adsorb the magnetic substance on the surface of the nuclear particles; and polymerizing a polymerizable monomer in the presence of said matrix particle to form a polymer layer on the magnetic substance layer.