Development of a dual-emitting nanohybrids ratiometric fluorescent probe for highly sensitive detection of L-cysteine based on Cu-Ag alloy nanoclusters and carbon quantum dots

In this study, we successfully synthesized Cu-Ag alloy nanoclusters (CuAgCs) by introducing Ag, which exhibited superior stability compared to Cu nanoclusters (CuNCs). Additionally, carbon quantum dots (CQDs) with an impressive quantum yield of 26% were prepared. By combining short-wavelength CQDs with long-wavelength CuAgNCs, ratiometric fluorescent probes capable of dual emission with peaks at 468 nm (F468) and 560 nm (F560) were developed for detecting L-cysteine (L-Cys). The detection mechanism involves the aggregation-induced emission enhancement (AIEE) effect of CuAgNCs in the presence of L-Cys, resulting in an increase in F560 while F468 remains unchanged. The fluorescence intensity ratio F560/F468 exhibits a linear relationship with L-Cys concentration in the range of 0–60 μM, with a low detection limit of 0.367 μM. Notably, the practical applicability of the fluorescent probe was validated through successful detection in real samples, achieving a high recovery rate of 98.7%-109%. These results demonstrate the promising potential of the developed fluorescent probe for practical applications. [Display omitted] •CuAgNCs that exhibit better stability compared to CuNCs have been synthesized.•A ratio probe based on CuAgNCs and CQDs has been successfully developed.•The ratio fluorescent probe has been successfully used for the detection of L-Cys.