Preparation of thermoresponsive and pH-sensitivity polymer magnetic hydrogel nanospheres as anticancer drug carriers

In this work, a novel therm and pH responsive magnetic hydrogel nanosphere poly(N-isopropylacrylamide-co-acrylic acid)/Fe3O4 (poly(NIPAAm-co-AA)/Fe3O4) has been successfully prepared. The magnetic hydrogel nanospheres with thermo and pH-sensitivity were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared-spectrometer (FT-IR), UV-vis absorption spectroscopy, and vibrating sample magnetometer (VSM). The magnetic hydrogel nanospheres exhibited uniform sphere structures and superparamagnetic property. Finally, the drug loading capacities and the releasing behavior of the magnetic hydrogel nanospheres were investigated with doxorubicin hydrochloride (DOX) as an anticancer drug model. The resulting magnetic hydrogel nanospheres exhibited high encapsulation efficiency (95%) to DOX under an appropriate condition. In vitro release experiments revealed that release was faster at pH 5.3 (37 degrees C) than at pH 7.4(25 degrees C) or pH 7.4(37 degrees C). The DOX-loaded magnetic hydrogel nanospheres also showed enhanced anticancer effect compared with the free drug in vitro. These presented results suggested that the magnetic hydrogel nanospheres have a potential as tumor targeting drug carrier. (C) 2011 Elsevier B.V. All rights reserved.