Multifunctional magnetic nanoparticles have emerged as important tools for targeted imaging and therapy, particularly in the diagnosis and treatment of diseases such as cancer and atherosclerosis. These nanoparticles, primarily composed of iron oxide, have been functionalized with targeting ligands such as peptides, antibodies, and small molecules to enhance their specificity and utility in biomedical applications. The surface of these nanoparticles is often coated with biocompatible materials to ensure stability, non-toxicity, and the ability to be functionalized for targeting and imaging purposes. Recent advancements have focused on the development of multifunctional nanoparticles that can serve both diagnostic and therapeutic roles, enabling multimodal imaging and targeted drug delivery. The synthesis and functionalization of these nanoparticles involve various chemical strategies, including conventional bioconjugation methods and click chemistry. These methods allow for the attachment of imaging agents, therapeutic molecules, and targeting ligands to the nanoparticle surface, enhancing their ability to bind to specific cells or tissues. For example, dextran-coated iron oxide nanoparticles have been used in cancer imaging to improve the accuracy of cancer staging and to detect metastases. Additionally, these nanoparticles have been utilized to image the inflammatory components of atherosclerosis and to target specific cell types such as macrophages. In cancer imaging, nanoparticles have been targeted to specific markers such as vascular cell adhesion molecule-1 (VCAM-1) and hepsin, enabling the visualization of tumor vasculature and prostate cancer. These nanoparticles have also been used in therapeutic applications, such as near-infrared light-activated therapy, where they can be used to target and destroy cancer cells. The development of theranostic nanoagents, which combine diagnostic and therapeutic functions, represents a promising direction in the field of nanomedicine. These agents have the potential to revolutionize the diagnosis and treatment of diseases by enabling precise targeting and real-time monitoring of therapeutic effects. Future research aims to further enhance the functionality and biocompatibility of these nanoparticles to improve their clinical applications.Multifunctional magnetic nanoparticles have emerged as important tools for targeted imaging and therapy, particularly in the diagnosis and treatment of diseases such as cancer and atherosclerosis. These nanoparticles, primarily composed of iron oxide, have been functionalized with targeting ligands such as peptides, antibodies, and small molecules to enhance their specificity and utility in biomedical applications. The surface of these nanoparticles is often coated with biocompatible materials to ensure stability, non-toxicity, and the ability to be functionalized for targeting and imaging purposes. Recent advancements have focused on the development of multifunctional nanoparticles that can serve both diagnostic and therapeutic roles, enabling multimodal imaging and targeted drug delivery. The synthesis and functionalization of these nanoparticles involve various chemical strategies, including conventional bioconjugation methods and click chemistry. These methods allow for the attachment of imaging agents, therapeutic molecules, and targeting ligands to the nanoparticle surface, enhancing their ability to bind to specific cells or tissues. For example, dextran-coated iron oxide nanoparticles have been used in cancer imaging to improve the accuracy of cancer staging and to detect metastases. Additionally, these nanoparticles have been utilized to image the inflammatory components of atherosclerosis and to target specific cell types such as macrophages. In cancer imaging, nanoparticles have been targeted to specific markers such as vascular cell adhesion molecule-1 (VCAM-1) and hepsin, enabling the visualization of tumor vasculature and prostate cancer. These nanoparticles have also been used in therapeutic applications, such as near-infrared light-activated therapy, where they can be used to target and destroy cancer cells. The development of theranostic nanoagents, which combine diagnostic and therapeutic functions, represents a promising direction in the field of nanomedicine. These agents have the potential to revolutionize the diagnosis and treatment of diseases by enabling precise targeting and real-time monitoring of therapeutic effects. Future research aims to further enhance the functionality and biocompatibility of these nanoparticles to improve their clinical applications.