Ferrofluids of magnetic multicore nanoparticles for biomedical applications

For a variety of magnetically based biomedical applications, it is advantageous to use sedimentation stable suspensions of relatively large(d > 420 nm) magnetic core-shell nanoparticles. Water-based suspensions of multicore nanoparticles were prepared by coating of the particles (synthesized by means of a modified alkaline precipitation method) with a carboxymethyldextran shell. The resulting ferrofluids were structurally and magnetically characterized. It was found that these fluids show a specific heating power of about 60W/g (f = 400 kHz, H = 10kA/m). This value was increased upto 330W/g by a simple fractionation method based on centrifugation. Finally, the cellular uptake of the multicore nanoparticles was demonstrated. (c) 2009 Elsevier B.V. All rights reserved.