Composite of magnetic drug carriers with thermo-responsive polymer for controlled drug release

The present paper describes organic/inorganic composite nanoparticles (CNPs) with a thermal response for biomedical applications. The composite nanoparticles are composed of a thermo-responsive polymer shell of hydroxypropyl cellulose (HPC) and a magnetic FeOx/silica core that exhibits a heat-generation capability against alternating magnetic fields. The heat-generation capability of the FeOx core was improved by modifying the synthesis process of the NPs to oxidize nonmagnetic FeO to magnetic Fe3O4. The HPC shell is observed by transmission electron microscopy after coating FeOx/silica NPs with HPC; the coating is confirmed by the increase of the hydrodynamic size of NPs and the weight loss with thermogravimetry. The FeOx/silica/HPC composite NPs exhibit a thermal response, which is confirmed by the temperature-dependent hydrodynamic size of the NPs. These results indicate that the thermo-responsive FeOx/silica/HPC composite particles have a potential as a drug carrier with a capability of controlled release. (C) 2016 The Japan Society of Applied Physics