Multifunctional iron oxide nanoparticles (MNPs) are promising magnetic biomaterials for drug delivery, offering high specificity, efficiency, and bioavailability. These nanoparticles, based on iron oxide, are used in biomedical applications such as targeted drug delivery, cancer treatment, and MRI imaging. Their unique properties, including superparamagnetism, biocompatibility, and biodegradability, make them ideal for various biomedical applications. MNPs can be synthesized using various methods, including co-precipitation, thermal decomposition, microemulsion, sol-gel, hydrothermal, and biological approaches. Each method has its advantages and limitations, with co-precipitation being the most widely used due to its simplicity and high yield. Surface functionalization of MNPs is crucial for enhancing their targeting ability, biocompatibility, and drug loading capacity. Common functionalization strategies include the use of polymers such as dextran and PEG, which improve the stability and circulation time of MNPs in the bloodstream. MNPs are also used in biomedical imaging, cell separation, and magnetic hyperthermia. Their magnetic properties, such as saturation magnetization, remanence, and coercivity, are critical for their functionality in biomedical targeting mechanisms. The use of external magnetic fields enhances the delivery efficiency of MNPs to tumor sites, improving their therapeutic impact. MNPs have shown great potential in cancer treatment, particularly in magnetic hyperthermia and targeted drug delivery. However, challenges such as particle aggregation, toxicity, and limited commercial availability remain. Overall, MNPs are promising candidates for various biomedical applications due to their unique properties and versatility.Multifunctional iron oxide nanoparticles (MNPs) are promising magnetic biomaterials for drug delivery, offering high specificity, efficiency, and bioavailability. These nanoparticles, based on iron oxide, are used in biomedical applications such as targeted drug delivery, cancer treatment, and MRI imaging. Their unique properties, including superparamagnetism, biocompatibility, and biodegradability, make them ideal for various biomedical applications. MNPs can be synthesized using various methods, including co-precipitation, thermal decomposition, microemulsion, sol-gel, hydrothermal, and biological approaches. Each method has its advantages and limitations, with co-precipitation being the most widely used due to its simplicity and high yield. Surface functionalization of MNPs is crucial for enhancing their targeting ability, biocompatibility, and drug loading capacity. Common functionalization strategies include the use of polymers such as dextran and PEG, which improve the stability and circulation time of MNPs in the bloodstream. MNPs are also used in biomedical imaging, cell separation, and magnetic hyperthermia. Their magnetic properties, such as saturation magnetization, remanence, and coercivity, are critical for their functionality in biomedical targeting mechanisms. The use of external magnetic fields enhances the delivery efficiency of MNPs to tumor sites, improving their therapeutic impact. MNPs have shown great potential in cancer treatment, particularly in magnetic hyperthermia and targeted drug delivery. However, challenges such as particle aggregation, toxicity, and limited commercial availability remain. Overall, MNPs are promising candidates for various biomedical applications due to their unique properties and versatility.