An Advanced Thermal Decomposition Method to Produce Magnetic Nanoparticles with Ultrahigh Heating Efficiency for Systemic Magnetic Hyperthermia. Issue 12 (1st November 2022) - Demessie, Ananiya A.
Abstract: Due to the limited heating efficiency of available magnetic nanoparticles, it is difficult to achieve therapeutic temperatures above 44 °C in relatively inaccessible tumors during magnetic hyperthermia following systemic administration of nanoparticles at clinical dosage (≤10 mg kg −1 ). To address this, a method for the preparation of magnetic nanoparticles with ultrahigh heating capacity in the presence of an alternating magnetic field (AMF) is presented. The low nitrogen flow rate of 10 mL min −1 during the thermal decomposition reaction results in cobalt‐doped nanoparticles with a magnetite (Fe3 O4 ) core and a maghemite (γ‐Fe2 O3 ) shell that exhibit the highest intrinsic loss power reported to date of 47.5 nH m 2 kg −1 . The heating efficiency of these nanoparticles correlates positively with increasing shell thickness, which can be controlled by the flow rate of nitrogen. Intravenous injection of nanoparticles at a low dose of 4 mg kg −1 elevates intratumoral temperatures to 50 °C in mice‐bearing subcutaneous and metastatic cancer grafts during exposure to AMF. This approach can also be applied to the synthesis of other metal‐doped nanoparticles with core–shell structures. Consequently, this method can potentially be used for the development of novel nanoparticles with high heating performance, further advancing systemic magnetic hyperthermia for cancer treatment. Abstract : The low nitrogen flow rate during the thermal decomposition reaction leads to the production of core (magnetite)–shell (maghemite) iron oxide nanoparticles (Co‐Fe3 O4 /γ‐Fe2 O3 ) with an ultrahigh heating efficiency in the presence of an alternating magnetic field (AMF). These nanoparticles efficiently accumulate in cancer tumors after systemic administration and elevate the intratumoral temperature to 50 °C upon exposure to AMF.