Facile method for synthesis of hollow porous magnetic microspheres with controllable structure

Hollow porous magnetic microspheres with strong magnetization and controllable structure were prepared via a facile electrostatic self-assembly of the positively charged Fe(3)O(4) nanoparticles onto the surface of the negatively charged poly(N,N'-methylenebisacrylamide-co-methacrylic acid) (P(MBAAm-co-MAA)) microspheres with subsequent removal of the polymer core through calcination at high temperature. The shell thickness was facilely tuned through the ratio between Fe(3)O(4) and polymer, and the void space was conveniently changed through the size of polymer microspheres. The hollow magnetic microspheres possessed high saturation magnetization value (51.38 emu/g) and porous structure with high specific surface area (108.04 m(2)/g). Based on these properties, the drug loading and release behaviors were investigated, which indicated that the hollow magnetic microspheres exhibited a controlled release process.