Ratiometric fluorescent detection of sulfide ions in Radix Codonopsis and living cells based on PVP-supported gold/copper nanoclusters with tunable dual emission.

Herein, a novel fluorometric-sensor with dual-emission system was constructed on the basis of polyvinylpyrrolidone (PVP) and 2-mercaptobenzothiazole (MBT) co-functionalized gold/copper nanoclusters (PVP/MBT-Au@CuNCs) by a facile and eco-friendly one-pot approach. The sensor exhibited ratiometric fluorescence emission (F _{590 nm} /F _{422 nm} ) for visual and selective detection of S ^2- with a sensitive detection limit of 11.9 nM. Besides, fluorescence quenched sensing of S ^2- was chalked up by a quickly selectivity monitoring time of 30 s, owing to the strongly binding of Cu ₂ S and Au ₂ S by hard-soft-acid-base theory and the destruction of the aggregated structure of PVP/MBT-Au@CuNCs. Furthermore, the platform also provided the portable analysis for visual detection of S ^2- by capturing the change in fluorescence color with a single dual-emissive ratiometric paper strip. It is worth mentioning that the fluorescent gold-copper nanoclusters showed excellent application activities in the selective detection of S ^2- in Radix Codonopsis or Tremella samples and recognition of S ^2- in HeLa cells or macrophages by confocal microscopy fluorescent imaging. Overall, the sensing system paved a new avenue for effectively developing a convenient ratiometric fluorescent sensor platform for evaluating the safety of food with S ^2- pollution in environment and biological system.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier B.V. All rights reserved.)