Fluorometric and colorimetric dual-mode sensing of -glucosidase based on aggregation-induced emission enhancement of AuNCs

Herein, a fluorometric and colorimetric dual-mode assay platform used for alpha-glucosidase (alpha-Glu) activity sensing based on aggregation-induced emission enhancement (AIEE) of AuNCs was developed for the first time. The quantum yield (QY) and fluorescence lifetime of AuNCs were successfully ameliorated by Ce3+-triggered AIEE (Ce@AuNCs). Subsequently, on the basis of the inner filter effect (IFE) and dynamic quenching effect (DQE) between 2,6-dichlorophenolindophenol (DCIP) and Ce@AuNCs as well as the reduction of DCIP by ascorbic acid (AA) generated from alpha-Glu-catalyzed hydrolysis of l-ascorbic acid-2-O-alpha-d-glucopyranosyl (AA2G), the marriage of fluorometric and colorimetric modes applied for alpha-Glu activity monitoring was achieved. Besides, the feasibility of this dual-mode sensing system was confirmed by the assays versus potential interfering substances and in real samples. In particular, this system was further applied to evaluate natural alpha-Glu inhibitors (AGIs) including luteolin, apigenin, and hesperidin. Overall, the multi-mode optical sensor newly designed here has the potential for the accurate discovery of natural anti-diabetes drugs and the therapy of diabetes. This work firstly developed a fluorometric and colorimetric dual-mode assay platform for alpha-glucosidase sensing based on aggregation-induced emission enhancement of AuNCs.