Multifunctional Magnetic Nanoparticles: Synthesis, Modification and Biomedical Applications

Due to their unique characteristics including superparamagnetic or fluorescent properties and small size comparable to biomolecules, multifunctional magnetic nanoparticles (MFMNPs) have emerged as novel bioimaging, diagnostic and therapeutic agents in biomedical field. The combinations of various nanostructured materials with different: propeties and magnetic nanoparticles (MNPs) can offer synergetic multifunctional nanomedical platforms, which make it possible to accomplish multimodal imaging and simultaneous diagnosis and therapy. This review summarizes the synthesis of MNPs and fabrication of MFMNPs, especially focuses on the three types of MFMNPs-core/shell MFMNPs, dumbbell MFMNPs and multicomponent hybrid nanoparlicles. Furthermore, to perform real-time monitoring and drug treatment with high accuracy in vivo, stabilizing modification and target modification of MFMNPs are needed to enhance the stability of MFMNPs in physiological environment and localize MFMNPs in the special area in vivo. This paper reviews the general strategies for surface modification of MFMNPs and biomedical applications of these MFMNPs for multimodal imaging, target-specific drug delivery, gene transfection and so on. The development of MFMNPs fusing multiple fluorescent dyes, drugs, and MNPs into a single nanoprobe should provide superior fluorescent, enhanced magnetic resonance imaging (MRI) contrast, and targeted delivery capabilities. Finally, problems to be solved in the current research are also pointed out.