Carbon-dot-based ratiometric fluorescent probe of intracellular zinc ion and persulfate ion with low dark toxicity.

Abstract

Metal ions and anions play significant roles in biological systems and industrial processes, therefore it is important to develop good fluorescent probes to detect metal ions and anions. Here, N,O-co-doped carbon quantum dots (CDs) that could detect Zn2+ via a ratiometric fluorescence method were fabricated. The reaction between the as-prepared CDs and zinc acetate gave the composite CDs-Zn, in which fluorescence changed ratiometrically upon addition of S2 O8 2- . With change in excitation light, the emission peaks of the CDs and CDs-Zn were kept fixed while intensity changed. CDs and CDs-Zn exhibited good photostability, thermal stability, selectivity, and strong anti-interference ability. In addition, CDs and CDs-Zn displayed low dark toxicity under physiological temperatures. Ratiometric fluorescence imaging of intracellular Zn2+ and S2 O8 2- was carried out in living HeLa cells for both of these probes. Compared with reported ratiometric fluorescent hybrid nanosensors based on organic dyes and inorganic nanomaterials, the as-prepared CDs and CDs-Zn had low toxicity, and were easy to synthesize.