Ce3+-induced fluorescence amplification of cooper nanoclusters based on aggregation-induced emission for specific sensing 2,6-pyridine dicarboxylic acid

A straightforward, cost-effective and biocompatible reduction approach was applied to fabricate soluble but non-luminous glutathione-stabilized copper nanocluster (GSH-CuNCs). Surprisingly, as high as 1×10 3 times fluorescence enhancement was acquired when Ce 3+ was injected at an extremely low concentration of only 18 µM. Ce 3+ outperformed other rare-earth metal ions in terms of inducing fluorescence amplification of the non-luminous GSH-CuNCs. Furthermore, Ce 3+ was employed as a linker between GSH-CuNCs and target of 2,6-pyridine dicarboxylic acid (DPA), an excellent anthrax biomarker. As a result, the Ce 3+ /GSH-CuNCs ensemble was developed as a novel fluorescence probe based on aggregation-induced emission (AIE) mechanism to detect DPA in the "on-off" mode at a fast rapid. The fluorescence intensity of ultra-bright Ce 3+ /GSH-CuNCs was gradually quenched along with the progressive increase in DPA concentration, resulting from a stronger coordination ability between Ce 3+ and DPA than Ce 3+ and GSH, Ce 3+ would fail to interact with GSH and detached from the surface of CuNCs. A good linear relationship from 0.3 µM to 18 µM was obtained under optimal conditions for DPA determination, with a limit of detection (LOD) of 0.19 µM. Additionally, its feasibility was successfully validated by testing actual water samples. This proposed method significantly promote the construction of ensemble type sensors in the form of metal-ion/metal nanoclusters based on AIE for measuring other analytes.