8 - Facile and fast synthesis of lanthanide nanoparticles for bio-applications

Abstract

The scientific community has, for a long time, been fascinated with lanthanide-doped dielectric nanocrystals. This is mainly due to the fact that their narrow band emissions, large Stokes and anti-Stokes shifts, long lifetimes, superior stability, low toxicity, feasibility to many excitation and emission wavelengths, weak fluorescence background, and, in several situations, large penetration depth give rise to a wide range of applications in optical and electronic devices. Additionally, since they have a unique 4f orbital configuration and biocompatibility, they are considered to be very promising in theranostics. In fact, many works report on the new perspectives on diagnosis, therapy, fluorescence imaging, and thermometry offered by lanthanide-doped nanoparticles. Recently, however, the attention has been placed on near-infrared imaging due to a deeper light penetration, absence of autofluorescence, high signal-to-noise ratio, and low tissue damage. This, in turn, is reflected in a huge demand for luminescence nanoparticles operating in spectral ranges known as biological windows. In this chapter, we report the main synthesis methods utilized for the production of lanthanide-doped dielectric nanoparticles, the recent progresses of their diagnostic and therapeutic applications, and the enhancement of their spectroscopic properties as achieved by different methods of surface functionalization and/or coating.