Highly photoluminescent carbon dots-based fluorescent chemosensors for sensitive and selective detection of mercury ions and application of imaging in living cells

Based on two kinds of hetero atom doping carbon dots (CD-1, CD-2) with brilliant fluorescent quantum yield and other fluorescence properties, two new sensors were prepared and characterized as novel fluorescent probes for detecting mercury ions in pure aqueous solution with a broad pH. Mercury ions can be captured by the carboxyl groups of these two kinds of carbon dots to form nonfluorescent complexes, resulting in a strong quenching. It suggested that both CD-1 and CD-2 exhibited high sensitivity and selectivity toward mercury ions: the linear ranges of CD-1 and CD-2 were estimated to be 1-12 μM and 1-15 μM while the limit of detection (LOD) was calculated to be 226 nM and 845 nM, respectively. Furthermore, these two kinds of CDs were applied to intracellular sensing and imaging of mercury ions as a consequence of the fluorescence properties and the established low cytotoxicity.