Chapter 6 - Upconversion nanoparticles: a toolbox for biomedical applications

Abstract

Lanthanide-doped upconversion nanoparticles can emit ultraviolet, visible, or near-infrared light when they are exposed to a near-infrared laser. This exceptional optical property makes them promising for bioimaging applications, with attractive advantages such as a large penetration depth and the ability to avoid autofluorescence from biotissues. Meanwhile, the variety of rare earth that could be employed in upconversion nanoparticles results in other unique properties such as clinical imaging contrast. Because of these potentials, upconversion nanoparticles have been developed as a toolbox holding a plethora of types to be chosen from by the biomedical field. In this chapter, we introduce the recent advances in upconversion nanoparticles from the aspects of their synthesis, structure and composition control, energy transfer mechanism, fluorescent properties, surface modification aimed at imaging and therapy, and so on.