(INVITED)Adjustable near-infrared fluorescence lifetime emission of biocompatible rare-earth-doped nanoparticles for in vivo multiplexing

Rare-earth-doped inorganic nanocrystals are an important class of nanoparticles for bioimaging applications due to the facility providing them with tailored emissions in visible and near-infrared regions electromagnetic spectrum. Recently it has become interest engineer dopant composition these materials order enable multiplexed lifetime imaging autofluorescence-free vivo bioimaging. Herein we report a simple approach obtain different fluorescence lifetimes Yb3+emission (2F5/2 → 2F7/2) Nd3+, Yb3+, Tm3+ co-doped NaGdF4 by only changing their crystal size while keeping hydrodynamic diameter constant. This allowed straightforward transformation infrared images time domain into maps. The particles were then deployed as contrast agents mouse demonstrating multiplexing capability.