Active targeting and transport

Actively targeted nanoparticles (NPs) are founded on the ability of ligands to bind with a surface marker of a target cell or tissue. Unlike passively targeted NPs that depend solely on the leakiness of blood vessels and passive diffusion, actively targeted NPs bind to target cells, allowing better distribution in target tissue, higher internalization into target cells, accumulation on circulating neoplastic cells, and passage across semipermeable barriers. Despite the many potential advantages of actively targeted NPs, there are no currently approved actively targeted NPs used clinically. This chapter focuses on the chemical interactions of actively targeted NPs with their target, the differences between commonly used ligands for actively targeted NPs and associated challenges, and the various diseases that have been studied using actively targeted NPs.