Carbon dots-based fluorescence and UV–vis absorption dual-modal sensors for Ag + and l -cysteine detection

Although a multitude of carbon dots (CDs) based sensors have spring up, most of them are fluorescent probes. Other optical properties, such as optical absorption has been neglected for too long. In order to improve reliability of results, making use of fluorescence (FL)/UV–Vis absorption dual signaling probes is an effective approach. Herein, orange emissive CDs were synthesized and utilized as FL/UV–vis dual-functional probes for the first time, to selectively detect Ag + and l -Cysteine (L-Cys), with low limit of detection of 0.05 μM and 0.02 μM. In addition, CDs have the advantages including unique stability, good biocompatibility and high sensitivity, which demonstrate excellent performance in selectively detecting intracellular changes of Ag + and L-Cys. This work provides a feasible way to construct multifunctional biosensors for the potential applications in environmental survey and biological assay.