Lysosome-targeted dual-emissive carbon dots for ratiometric optical dual-readout and smartphone-assisted visual determination of Hg2+ and SO32−

Abstract

Smartphone-assisted visual assay not only expands quantitative analysis but also enhance real-time on-site sensing capabilities. Herein, lysosome-targeted dual-emissive carbon dots (L-CDs) can not only recognize Hg2+ and SO32− by ratiometric fluorescence and ratiometric absorption, but also visually quantify Hg2+ and SO32− by smartphone-assisted method. With monitoring of intrinsic ratiometric fluorescent variation (I580/I468), L-CDs are developed as an effective sensing platform for ratiometric fluorescent successive identification of Hg2+ and SO32− accompanying with continuous fluorescence variation of blue, purplish pink, pink, and light yellow. With detecting of inherent ratiometric absorption change (A538/A206), L-CDs are also constructed as an efficacious sensing terrace for ratiometric absorption consecutive discrimination of Hg2+ and SO32−. More crucially, integrating continuous fluorescence color change and color recognizer APP in the smartphone, visual quantification of Hg2+ and SO32− can be accomplished on the basis of the ratio of red value and blue value (R/B) with linear ranges of 0–130 and 0–850 µM, respectively, as well as LOD of 8.4 and 12.9 nM, respectively. More interestingly, confocal fluorescent imaging of HeLa cells further verifies that L-CDs can be regarded as favorable biosensors for on-site, real-time differentiation of Hg2+ and SO32− in vitro and in vivo with ratiometric manners.