Magnetic Nanoparticles for Self Controlled Hyperthermia Treatment of Tumors Y. Haik 1,2 , V. Mohite 2 ,C-J Chen 2 1,2 Department of Mechanical Engineering, United Arab Emirates University, Al Ain UAE 2 Center for Nanomagnetics and Biotechnology, Florida State University, FL 32310 E-mail: yhaik@uaeu.ac.ae ABSTRACT Hyperthermia has been gaining a lot of interest as a method for treating cancer particularly as an adjunct to other modalities such as radiotherapy and chemotherapy. Self controlled magnetic hyperthermia takes advantage of producing localized heating by subjecting nanomagnetic particles to an alternating magnetic field. The temperature rise at the cancer tissue is controlled by the particles Curie temperature. In the present paper 4 ) 2 ( 5 . 0 5 . 0 O Fe Gd Zn Mn x x - nanoparticles were synthesized using chemical co precipitation technique to obtain particles with Curie temperature of 42 and with high value f magnetization. These particles showed high promise for self controlled magnetic hyperthermia application. INTRODUCTION Hyperthermia is temperature elevation of tissue with the aim of receiving therapeutic benefits. Knowledge about heat treatment of tumors is as old as the written text in medicine [1]. Unfortunately, the enthusiasm of modern cancer research for this modality has been sporadic until recently. In the 1960s, researchers confirmed that cancer cells are more vulnerable to heat than their normal counterparts. In the U.S., the hegemony of the three official modalities -- surgery, radiation and chemo - - lasted until the 70s, when hyperthermia was taken off the ACS blacklist (Unproven Therapies List). In late 70s and early 80s several trials had shown that hyperthermia combined with radiation produced superior results over radiation alone. Recently, the results of three European and one American phase III trials have become available. All these trials were well controlled, showing that the use of hyperthermia in combination with radiation therapy results in superior tumor response, tumor control, and survival as compared with radiation therapy alone [2] Magnetic hyperthermia is the method of heating body tissue using magnetic materials [3,4,5]. In this process magnetic material is introduced near the tumor then subjected to an oscillating magnetic field that will cause the material to heat. Self controlled hyperthermia controls the spot overheating that causes necrosis [6]. The self control of overheating is provided by controlling the materials Curie temperature. Nanomagnetic particles with Curie temperature of 42-43 o C are suitable for producing biocompatible heat source at the tumor site when subjected to an alternating field. Once the particles temperature reaches the Curie temperature they will stop responding to the applied field, hence the heating will be maintained at the Curie temperature. This study is aimed at producing nanomagnetic particles with Curie temperature of 42-43 o C. Mn-Zn Ferrite nanoparticles have gained a lot of consideration mainly because of the ability to vary their properties by varying the proportions of the constituent metals [7-9]. These particles are of the form Zn x Mn (1-x) Fe 3 O 4 and are synthesized by physical as well as chemical means. Chemical co- precipitation is one of the various methods used to synthesize nanoparticles. Gd-substituted Mn-Zn ferrite particles are made by chemical co precipitation method. The particles formed are of the nature 4 ) 2 ( 5 . 0 5 . 0 O Fe Gd Zn Mn x x - . The effect of varying Gd proportions on the Curie temperature of the nanoparticles is reported. MATERIALS AND METHODS Mn-Zn-ferrite particles and Gd substituted Mn-Zn- Ferrite particles are obtained via chemical co- precipitation and ferritization. First the metal salts are co-precipitated into hydroxides. This is done by addition of aqueous solution of metal salts in water to the co precipitating base (e.g. NaOH, CH 3 NH 3 OH etc.). For the case of Mn-Zn Ferrite particles the reaction occurs as follows: NSTI-Nanotech 2005, www.nsti.org, ISBN 0-9767985-0-6 Vol. 1, 2005 300