科研之友
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摘要
In this study, we present a facile one-step solvothermal strategy for the fabrication of sulfur-nitrogen co-doped carbon dots (SNCDs) using p-phenylenediamine and cysteamine hydrochloride as the precursors. The as-prepared SNCDs possess well monodispersed and nearly spherical morphology, and present favorable optical performances encompassing strong yellow-green fluorescence and excitation wavelength-independent fluorescence behavior with the maximum excitation/emission wavelength at 420/550 nm. More strikingly, the emission of SNCDs is effectively quenched by hypochlorous acid (HOCl/ClO-), whereas the SNCDs-HOCl aggregate can be released by zinc(II) ions (Zn2+) causing a fluorescence enhancement/recovery process. As such, we designed a SNCD-based fluorescence "off-on'' nanosensor for HOCl and Zn2+ detection. The "turn off'' mode enables the quantitative analysis of HOCl with a linear range of 0.18-4.22 mu M and a detection limit of 0.021 mu M. And the quantitative range for Zn2+ detection based on the "turn on'' process is from 8.41 to 84.12 mu M with a detection limit of 0.30 mu M. Moreover, the fluorescent nanoprobe was applied for the assay of HOCl/ClO- and Zn2+ in water samples with satisfactory recovery values and in MCF-7 cell imaging with negligible autofluorescence, indicating its promising application potential in chemical, environmental and biological systems.
