Dual-Targeted Therapy and Molecular Imaging with Radiolabeled Nanoparticles

Radiolabeled targeted nanoparticles have been extensively studied for medical applications. Their multifunctionality and multivalency (among other properties) make them suitable candidates to target different diseases by means of pharmacophore groups for molecular, cellular, and/or tissue targeting. They have been used for molecular imaging and as drug delivery systems to improve drug efficacy and decrease side effects by passive accumulation of drugs in healthy tissues. Metallic nanoparticles can be radiolabeled or be radioactive themselves in order to deposit a large amount of energy into malignant cells, which produces irreversible damage. Because of their high surface area, these can be functionalized with small molecules and biomacromolecules for targeted radiotherapy. Moreover, their quantum size effect and resulting properties recently proved to produce hyperthermia. Polymeric nanoparticles are also acquiring importance in molecular imaging as diagnostic and therapeutic agents, due to their biocompatibility, biodegradability, and pharmacokinetic advantages, including the ability for controlled drug release or targeted radiotherapy. Both metallic and polymeric nanoparticles have been proposed as new, smart, pharmaceutical devices to produce dual-targeted therapy and molecular imaging. In this chapter, we will discuss the development and potential medical applications of radiolabeled metallic and polymeric nanoparticles as intelligent targeted systems.