Preparation and characterization of magnetic nanoparticles embedded in microgels

This article describes the magnetically responsive microgel that consists of a small iron oxide magnetic nanoparticles (similar to 15 nm in diameter) embedded in a biocompatible microgel varying from similar to 65 to similar to 110 nm in diameter. These systems show great promise as active component of microscale and nanoscle devices and are expected to have wide applicability in various biomedical applications. Polymeric microgels have been prepared by emulsion free copolymerization of thermoresponsive N-isopropylacrylamide and acrylic acid with a water-soluble persulfate initiator. The obtained microgel magnetic composite particles possess a lower critical solution temperature (LCST) in water solutions, with a rapid decrease of the particle size being observed at elevated temperatures. The morphology and elemental composition of the composites were characterized by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy (FTIR). (C) 2007 Elsevier B.V. All rights reserved.