Facile Fabrication of Water-Soluble Magnetic Nanoparticles and Their Spherical Aggregates

In this paper, we report a facile synthetic approach for preparing water-soluble Fe 3 O 4 nanoparticles with a surface-surrounded layer by the use of polyethylene glycol(5) nonylphenyl ether (NP5) and cyclodextrin (CD) in aqueous medium and also for building nanostructured spherical aggregates from individual magnetic nanoparticles, which were dependent on the concentration of CD and NP5, respectively. The morphology of Fe 3 O 4 nanoparticles was studied by transmission electron microscopy. The mesoporous, spherical aggregates of Fe 3 O 4 particles possessed a BET surface area of ca. 141.1 m 2 g -1 without compromising that of the separated Fe 3 O 4 nanoparticles with coating (164.6 m 2 g -1 ) and still possessed magnetic properties. This method is very meaningful because it directly produces water-soluble magnetic nanoparticles, which is very important for applications of magnetic nanoparticles in biomedical fields and nanostructured spherical aggregates as magnetic carriers.