Brightly blue triazine-doped carbon dots for selective determination of Cu(II) in environment and imaging in cell

Abstract Whether as a microelement or a highly toxic metal ion, it has a standing demand to the development of simple, facile and sensitive platform for copper ion (Cu(II)) assay. Here we reported the use of 2,4,6-trihydrazinyl-1,3,5-triazine (THT) and citric acid (CA) as precursors to fabricate carbon dots (C-dots) through one-spot hydrothermal approach at 200 °C for 10 h. The maximum excitation and emission wavelengths at ∼355 and ∼440 nm, respectively, of the triazine-doped C-dots with ∼27.6 % QY were observed. The functional groups such as −COOH and -NH2 anchored on the surface of the C-dots, which led to the pH-dependent emission behavior. Also, they can coordinate with Cu(II) to form an absorbent complex, quenching the blue fluorescence of the triazine-doped C-dots by inner filter effect, and the aggregation-induced quenching also contributed to the fluorescence decay. A chemosensory platform for Cu(II) with an 8.6 nM detection limit in a concentration ranging from 0.01–12.5 μM was therefore established. The triazine-doped C-dots were successfully applied in not only the determination in environment but also the imaging in cell of Cu(II), demonstrating their excellent applicability.