Yb-Based Nanoparticles with the Same Excitation and\nEmission Wavelength for Sensitive in Vivo Biodetection

Abstract

Near-infrared\nluminescent emission has been widely used as a signal for biological detection with its\nhigh spatial resolution and fast response. Rare-earthdoped nanoparticle–dye\ncomposites have diverse advantages of a wide operation wavelength\nand remarkable light stability, while the application is limited by\nthe low luminescence quantum yield of rare-earth nanoparticles. Hence,\nin this work, we use a singly Yb doped nanoparticle that has strong\nluminescence emission at 975 nm under excitation at the same wavelength\nas an energy donor to construct the detection system. An inner filter\npair, composed of core–shell nanophosphor NaYF₄/20%Yb@NaYF₄ (1:2) nanocrystals (csYb) as a luminescent beacon and ClO^–-responsive cyanine dye Cy890 as a filtering agent,\nwas designed as a model. With a time-gated detection mode, the nanocomposites\nrealize the detection limit at 0.55 ppb as demonstrated in a ClO^– detection trial. The csYb&Cy890 nanocomposites\ncan also monitor ClO^– by luminescence signals in\nboth living cells and mice models.