Long-Term Toxicity of Silica-Coated Iron Oxide Nanocrystalline Clusters Used for Magnetic Hyperthermia Applications

Nanobiomaterials play a crucial role in healthcare, offering exceptional applications in advanced diagnostics, targeted drug delivery, tissue engineering, imaging, and hyperthermia therapy. Iron oxide nanocrystalline clusters (IONC) have emerged as a versatile and promising class of nanobiomaterials due to their unique properties at the nanoscale enabling precise interactions with biological systems, thereby paving the way for innovative medical applications. The interactions of these nanomaterials with the cells, tissues, and microenvironment can reveal the biocompatibility or harmful effects within the biological systems; therefore, a systematic understanding of the toxicity parameters of these materials is essential. The solvothermal synthesized IONC was characterized and assessed for in vitro cytotoxicity on HeLa and MCF-7 cell lines as well as in vivo toxicity on Swiss albino mice. The average size of synthesized superparamagnetic IONC was found to be 230 nm from TEM analysis. These clusters exhibited promising efficiency for magnetic hyperthermia, with a SAR value of 104.1 W/g and an intrinsic loss parameter of 1.05 nH m 2 /kg −1 . The particles did not exhibit significant toxicity when tested on both cell lines. Blood parameter values remained within normal limits at 24 h, 5, and 75 weeks in the in vivo study. Histopathological evaluation using Perl’s stain revealed a dose-dependent iron accumulation in the liver and spleen, indicating these organs as the primary sites for iron metabolism, thereby contributing to its biocompatibility and non-toxicity. The result from the current study reveals that the synthesized silica-coated IONC can be efficiently used for hyperthermia application due to its biocompatibility as they do not show any significant in vitro or in vivo toxicity.