A Milestone in the Chemical Synthesis of Fe<sub>3</sub>O<sub>4</sub> Nanoparticles: Unreported Bulklike Properties Lead to a Remarkable Magnetic Hyperthermia
Idoia Castellanos-Rubio, Oihane K. Arriortua, Daniela Iglesias-Rojas, Ander Barón, Irati Rodrigo, Lourdes Marcano, J. S. Garitaonandía, I. Orúe, M. L. Fdez-Gubieda, Maite Insausti
Abstract
/kg at RT) and the extremely sharp Verwey transition (at around 120 K) shown by these NPs have no precedent. Moreover, the synthesis method has been refined to obtain NPs with octahedral morphology and suitable magnetic anisotropy, which significantly improves the magnetic hyperthemia performance. The heating power of properly PEGylated nano-octahedrons has been investigated by AC magnetometry, confirming that the NPs present negligible dipolar interactions, which leads to an outstanding magnetothermal efficiency that does not change when the NPs are dispersed in environments with high viscosity and ionic strength. Additionally, the heat production of the NPs within physiological media has been directly measured by calorimetry under clinically safe conditions, reasserting the excellent adequacy of the system for hyperthermia therapies. To the best of our knowledge, this is the first time that such bulklike magnetite NPs (with minimal size/shape polydispersity, minor agglomeration, and exceptional heating power) are chemically synthesized.