Synthesis of poly(ethylene glycol) and poly(vinyl pyrrolidone) co-coated superparamagnetic iron oxide nanoparticle as a pH-sensitive release drug carrier

The superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by thermal decomposition of the iron (III) acetylacetonate (Fe(acac)3) in poly(ethylene glycol) (PEG) solvent containing poly(vinyl pyrrolidone) (PVP). The average size of the SPIONs identified by TEM is in the range of 4–10 nm, which can be controlled by tuning the synthetic temperature and time. The results of FTIR and XPS indicate that the PEG and PVP were tightly attached to the surface of the SPIONs. The SPIONs coated with PEG and PVP performed very good colloidal stability in deionized water, as well as in other physiological buffers. The anticancer drug doxorubicin (DOX) was loaded onto SPIONs and the drug release properties were investigated. The result shows that the DOX has a very high encapsulation efficiency (more than 90%), and the release rate of DOX from drug loaded SPIONs is dramatically enhanced at acidic environment, while less amount of DOX is released at neutral pH 7.4, which indicates that the PEG and PVP co-coated SPIONs have a pH-sensitive drug release capability.