Nitrogen-doped carbon dots rapid and selective detection of mercury ion and biothiol and construction of an IMPLICATION logic gate.

Nitrogen-doped carbon dots (N-CDs) were prepared by adjusting the ratio of carbon sources (citric acid) and nitrogen sources (ethanolamine). This N-CDs fluorescent probe had been successfully applied to rapidly, sensitively and selectively determine the concentration of mercury ion (Hg) with a linear range of 0.1-5.0 μM and a limit of detection of 0.019 μM. In this work, it was demonstrated that N-CDs show the fluorescence response toward Hg when the carboxyl groups of citric acid reacts completely with the amino groups of ethanolamine. In addition, the quenched N-CDs/Hg system could be recovered by biothiol, such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), exhibiting a sensitive response toward Cys and Hcy over GSH in HEPES buffer. N-CDs could be used as a potential fluorescent bioimaging material due to their low toxicity and good biocompatibility. Furthermore, an IMPLICATION logic gate based on Hg and biothiol was constructed.