Seed emulsion polymerization was carried out to encapsulate Fe3O4nanoparticles with poly(N-isopropylacrylamide-co-methacrylic acid) for preparing polymeric microspheres(Fe3O4/P(NIPAM-co-MAA)) possessing magnetic and thermo-sensitive responses.The structure and morphology of microspheres were characterized by wide-angle X-ray diffraction (WAXD)

transmission electron microscopy (TEM)

dynamic light scattering (DLS)

thermogravimetric analysis (TGA)

vibrating specimen magnetometry (VSM) and BET specific surface area measurements.Ultraviolet-visible light (UV-Vis) spectroscopy was employed to investigate the drug loading and release behavior of microspheres using rhodamine B (RhB) as a model drug.It is indicated that the diameters of microspheres range from 80 nm to 200 nm

the specific surface area and average pore diameter are about 30.04 m2/g and 24.50 nm

respectively.The polymer content and Fe3O4 content of microspheres are about 73 wt% and 20 wt%

respectively.The saturated magnetization of microspheres reaches 16.49 emu/g

and the volume phase transition temperature (VPTT) is about 37.5℃.The RhB loading amount of microspheres is able to reach 16.38 mg/g.Under alternating magnetic field

the RhB release amount reaches 13.02 mg/g in simulative gastric-juice

and 10.47 mg/g in simulative intestinal-juice

respectively.Therefore

the synthesized polymeric microspheres (Fe3O4/P(NIPAM-co-MAA)) can be used as drug-carrier

and demonstrate good prospect in the targeted drug and drug controlled release.