Rhodamine B derivatives-modified upconversion nanoparticles as a fluorescent turn-off-on sensor for the highly sensitive detection of Cu 2+ and pyrophosphate.

Rhodamine B derivatives (RBP)-modified UCNPs (UCNPs@mSiO 2 -RBP) were developed as a fluorescent turn-off-on sensor based on FRET and IFE to detect Cu 2+ and pyrophosphate (PPi) with a wide linear response range (0-10 μM for Cu 2+ and 5-35 μM for PPi, much wider than that reported previously) and high sensibility (117 nM for Cu 2+ and 70 nM for PPi). The MTT experiments and the bioimaging experiments show its promising prospect in tissue imaging.