DOI: 10.1007/s10765-006-0138-y International Journal of Thermophysics, Vol. 28, No. 5, October 2007 (© 2007) Heating Effect in Biocompatible Magnetic Fluid 1 A. Skumiel, 2 A. J´ ozefczak, 2 M. Timko, 3 P. Kopˇ cansk´ y, 3 F. Herchl, 3,4 M. Konerack´ a, 3 and N. Tomaˇ soviˇ cov´ a 3 This work is devoted to the study of heating of a biocompatible magnetic fluid due to time-varying magnetic induction. The adsorption of dextran on magnetite particles was confirmed by IR spectroscopy. A considerable thick- ness of the surfactant layer (oleate sodium + dextran) of about 4.3nm pre- vents the formation of clusters made of nanomagnetic particles as evidenced by the fact that no maxima of the ultrasound wave absorption coefficient corresponding to cluster formation have been detected. The results show that the observed heating effect may be applied in hyperthermia treatments espe- cially in the preferable region of 500 – 800 kHz. An “H 2 – law” observed for the dependence of the SAR on the square of the amplitude of the magnetic field demonstrates the presence of superparamagnetic particles in the ferro- fluid. KEY WORDS: biocompatible magnetic fluid; hyperthermia; nanomagnetic particles; specific absorption rate. 1. INTRODUCTION Water-based magnetic fluids have been used for diagnostics and therapy in medical applications. In order to be used for biomedical purposes, mag- netic particles must be coated with a substance that ensures their stability and biocompatibility. Application of magnetic materials for hyperthermia 1 Paper presented at the Seventeenth European Conference on Thermophysical Properties, September 5-8, 2005, Bratislava, Slovak Republic. 2 Institute of Acoustics, Adam Mickiewicz University, Umultowska 85, 61–614 Pozna´ n, Poland. 3 Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Koˇ sice, Slovak Republic. 4 To whom correspondence should be addressed. E-mail:herchl@saske.sk 1461 0195-928X/07/1000-1461/0 © 2007 Springer Science+Business Media, LLC