Abstract

Iron Oxide Nanoparticles (IONPs) - Chiefly Magnetite (Fe₃O₄) and Maghemite (γ-Fe₂O₃) - remain among the most clinically advanced inorganic nanomaterials owing to their tunable superparamagnetism, low intrinsic toxicity relative to other metal oxides, and amenability to surface functionalization. This mini-review synthesizes current understanding of IONP synthesis routes (co-precipitation, thermal decomposition, hydrothermal, and green/biogenic methods), the structure–property relationships that govern their magnetic and catalytic behaviour, and their principal biomedical applications in drug delivery, antimicrobial therapy, Magnetic Resonance Imaging (MRI), and magnetic hyperthermia. Persistent translational bottlenecks - colloidal instability, batch-to-batch variability, and an incomplete biosafety picture at the sub-10nm scale - are critically examined. We conclude by outlining a forwardlooking research agenda centred on green-synthesized, multi-functional, stimuli-responsive IONP platforms designed to close the gap between laboratory promise and regulatory approval.

Keywords:Iron oxide nanoparticles; Magnetite; Superparamagnetism; Drug delivery; Antimicrobial resistance; Magnetic hyperthermia and Theranostics