Coumarin derivative dye sensitized NaYGdF4:Yb,Er nanoparticles with enhanced NIR Ⅱ luminescence for bio-vascular imaging

Lanthanide-doped biocompatible nanoparticles have promising applications in near-infrared second region imaging due to their high chemical stability,enhanced photostability and sharp emission bandwidth.However,the weak light absorption capacity limits the application of rare-earth nanoparticles(RENPs) for bioimaging.We prepared a coumarin-derived dye sensitized NaYGdF4:Yb,Er nanoparticle probe,in which the organic dye enhances photon absorption through the sensitization process,improving the luminescence efficiency of the rare earth particles near 1000 and 1500 nm.In addition,good water solubility and stability of the probe are imparted by coating the particles with amphiphilic polymers distearoyl phosphatidylethanolamine-polyethylene glycol(DSPE-PEG) and polyacrylic acid.This composite probe with good biocompatibility and NIR Ⅱ luminescence properties can be used for vascular imaging,providing a tool for the detection of hematologic-related diseases.

Effect of solvent on luminescence properties of re-dispersible LaF_3:Ln^(3+)(Ln^(3+)=Eu^(3+),Dy^(3+),Sm^(3+) and Tb^(3+)) nanoparticles

LaF3：Ln3＋ （Eu3＋, Dy3＋, Sm3＋ and Zb3＋） nanoparticles were prepared in different solvents such as water, EG （ethylene gly- col）, DMSO （dimethyl sulfoxide） and their mixed solvents at a relatively low temperature of 150 ~C by simple chemical route. All the prepared samples showed hexagonal phase and exhibited spherical morphology. The highest ltmainescence intensity was observed for the samples prepared in EG than the samples prepared in other solvents. However, the sample prepared in water showed anomalously higher luminescence intensity than that of the sample prepared in DMSO.