Advances in Luminescence Mechanism, Preparation and Biological Application of Upconversion Nanoparticles

As a new class of fluorescent-labeled materials, rare-earth doped upconversion nanoparticles (UCNPs) can absorb long wavelength near-infrared photons and emit short wavelength UV visible photons. It is capable of efficiently converting two or more low energy photons into high-energy photons. UCNPs have overcome the shortcomings of the traditional fluorescent labeling materials such as low sensitivity and poor photostability, and have become one of the promising alternatives to the traditional labeling materials. UCNPs excited by NIR have many advanta-ges, such as large anti-stokes shift, little damage to biological tissues, high tissue penetration ability, high conversion efficiency, no background fluorescence interference and no photo-bleaching effect. Therefore, it has become a new focus in many fields such as biosensing, imaging, tar-geted drug delivery, photodynamic therapy and analytical applications for bio-detection due to its outstanding characteristics. In this review, we briefly described the composition, luminescence mechanism and main synthetic methods of UCNPs, and focused on the recent progress in sen-sing, imaging and therapeutic applications. Finally, we reasonably analyzed the current insufficient of UCNPs and gave an outlook on its future development. © 2022 Cailiao Daobaoshe/ Materials Review. All rights reserved.