Inorganic lanthanide nanoprobes for background-free luminescent bioassays

Abstract

Luminescent bioassay techniques have been widely adopted in a variety of research and medical institutions. However, conven-tional luminescent bioassays utilizing traditional bioprobes like organic dyes and quantum dots often suffer from the interfer-ence of background noise from scattered lights and autofluores-cence from biological matrices. To eliminate this disadvantage, the use of inorganic lanthanide (Ln 3+)-doped nanoparticles (NPs) is an excellent option in view of their superior optical properties, such as the long-lived downshifting luminescence, near-infrared triggered anti-Stokes upconverting luminescence and excitation-free persistent luminescence. In this review, we summarize the latest advances in the development of inorgan-ic Ln 3+ -doped NPs as sensitive luminescent bioprobes from their fundamental physicochemical properties to biodetection, including the chemical synthesis, surface functionalization, optical properties and their promising applications for back-ground-free luminescent bioassays. Future efforts and pros-pects towards this rapidly growing field are also proposed.