Widely used in biomedical applications due to their superparamagnetic properties and biocompatibility. Commonly employed in targeted drug delivery, where the magnetic core allows guidance to specific sites under external magnetic fields, while PEG coating enhances circulation time and reduces immune clearance. Frequently used in magnetic resonance imaging (MRI) as contrast agents to improve tissue visualization. Applied in hyperthermia treatment for cancer, where alternating magnetic fields generate localized heat to destroy tumor cells. Also utilized in bioseparation processes, such as isolation of cells, proteins, or nucleic acids, due to easy magnetic separation and surface functionalization. PEG layer improves stability in physiological environments and minimizes nonspecific binding, making these nanoparticles suitable for in vivo applications.