Surface-Modified Iron Oxide Nanoparticles with Natural Biopolymers for Magnetic Hyperthermia: Effect of Reducing Agents and Type of Biopolymers

Magnetic fluid hyperthermia, a minimally invasive localized therapy that uses heat generated by magnetic nanoparticles under an AC magnetic field, is a complementary approach for cancer treatment that is excellent due to its advantages of being noninvasive and addressing only the affected region. Still, its use as a stand-alone therapy is hindered by the simultaneous requirement of nanoparticle biocompatibility, good heating efficiency, and physiological safe dose. To overcome these limits, the biocompatible magnetic nanoparticles’ heating efficiency must be optimized. Iron oxide nanoparticles are accepted as the more biocompatible magnetic nanoparticles available. Therefore, in this work, superparamagnetic iron oxide nanoparticles were synthesized by a low-cost coprecipitation method and modified with starch and gum to increase their heating efficiency and compatibility with living tissues. Two different reducing agents, sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH), were used to compare their influence. The X-ray diffraction results indicate the formation of a single magnetite/maghemite phase in all cases, with the particle size distribution depending on the coating and reducing agent. Citric acid functionalized water-based ferrofluids were also prepared to study the heating efficiency of the nanoparticles under a magnetic field with a 274 kHz frequency and a 14 kAm−1 amplitude. The samples prepared with NaOH display a higher specific loss power (SLP) compared to the ones prepared with NH4OH. The SLP value of 72 Wg−1 for the magnetic nanoparticles coated with a combination of starch and gum arabic, corresponding to an intrinsic loss power (ILP) of 2.60 nWg−1, indicates that they are potential materials for magnetic hyperthermia therapy.