Iron/cobalt/gold-based ferrofluids for potential biomedical applications

In ferrofluids, magnetic nanoparticles are suspended in carrier fluid and can orient their magnetic moment in the direction of the applied magnetic field. Iron/cobalt/gold-based ferrofluids were synthesized using two different methods. The size distribution and the composition of the nanoparticles were determined. Magnetization and UV-VIS spectra were measured. It was found that FeCoAu nanoparticles have larger magnetic moment then FeCo nanoparticles. Magnetization was used to estimate the thickness of magnetically inactive layer of the nanoparticles. Losses were measured in ac magnetic field at different frequencies and compared with losses in iron oxide-based ferrofluids. Higher magnetic moment and losses of FeCoAu-based ferrofluids at higher frequencies can lead to the potential biomedical applications of these ferrofluids such as magnetic drug delivery and hyperthermia treatment.