Multifunctional Magnetic Nanoparticles for Theranostic Applications

Abstract Organic functionalized magnetic nanoparticles (MNPs) are promising tools for advanced biomedical applications ranging from biosensing and bioseparations to diagnostic and therapeutic techniques such as magnetic resonance imaging, hyperthermia, and controlled drug delivery. The strength point of these tools is the combination of the magnetic properties of the core with the versatility of an organic coating able to impart new and specific functionalities. This chapter summarizes the most relevant achievements in this area, from the material synthesis to the in vitro and in vivo applications in the biomedical field. After a short introduction on the properties and syntheses of the nanomagnetic core, focus is centered on the approaches adopted to functionalize the surface of iron oxide nanoparticles. In particular, the role of different anchoring groups able to bond the coating to the oxide surface is discussed. In addition, the most important chemical routes adopted to conjugate specific functional biomolecules (e.g., optical imaging probes, molecular receptors, targeting molecules, peptides) on the organic-modified surface are reviewed. The multifunctionality of these organic–functionalized Fe 3 O 4 nanoparticles is the key to their successful applications and their use is becoming one of the most promising research areas in nanomedicine. In the last paragraphs of this chapter, an overview of the most important applications of MNPs is presented divided into two groups: in vitro applications in which MNPs are designed mainly for laboratory use or on-chip devices and in vivo applications whose main MNPs goal is the injection in a patient for diagnostic, therapeutic, or simultaneous diagnostic/therapeutic purposes (theranostics). Theranostics represents an important milestone in the development of cancer treatments. The ability to track chemotherapy drugs as they move through the body, as well as simultaneously targeting them at cancer cells, will improve the efficacy of the drugs, reduce side effects, and provide valuable data for development of new drugs.