Fluorescent and visual assay of H 2 O 2 and glucose based on a highly sensitive copper nanoclusters-Ce(III) fluoroprobe

Herein, we synthesized and characterized glutathione-capped copper nanoclusters (CuNCs) using a convenient one-pot chemical reduction approach based on glutathione as capping and reducing agents. The Ce(III) induced aggregation-induced emission of CuNCs to form a CuNCs-Ce 3+ fluoroprobe due to electrostatic and coordination interactions between Ce 3+ and CuNCs. In contrast to CuNCs, the fluorescent intensities (FLs) of CuNCs-Ce 3+ were enhanced by ~ 40-fold concomitant with 20-nm blue-shift of the maximum emission, and a 3.45-fold lengthening of the average fluorescent lifetime. The FLs of CuNCs-Ce 3+ were selectively quenched at 650 nm by hydrogen peroxide (H 2 O 2 ) via the redox reaction. Based on this phenomenon, the sensitive assay of H 2 O 2 was realized, and the linear range spanned over the range of 14–140 μM. Notably, the visualization of the fluorescence quenched effect of H 2 O 2 could be easily attained. Additionally, glucose could be specifically oxidized by glucose oxidase to produce H 2 O 2 , and thus the detection of glucose was achieved according to changes in the concentrations of H 2 O 2 . Under optimized conditions, the fluorescent assay of glucose based on the CuNCs-Ce 3+ system offered the linear range of 8–48 μM with detection limit of 2.4 μM. Meanwhile, high selectivity of the as-constructed fluorescent assay allows the sensitive detection of H 2 O 2 and glucose in real-world care products and human serum samples, showing a great application potential in their conventional monitoring.