Innovative fluorescence sensing platform for β-lactams based on acidity/basicity-sensitive graphdiyne quantum dots

Residues of β-lactam antibiotics (β-LA) in the environment have posed a great threat to human health, while lacking a simple, effective, and universal sensing method. Herein, basic fuchsin and graphdiyne (GDY) were used as precursors to prepare the first reported acidity/basicity-sensitive GDY quantum dots (S-GDY QDs). We propose a novel fluorescence-sensing strategy for β-LA detection based on the ability of β-lactamases to catalyze β-LA to form carboxylic acid, which further induces a change in the acidity/basicity of the solution and causes a decrease in the fluorescence intensity of S-GDY QDs. Furthermore, a fluorescence test strip sensing platform integrated with a smartphone was established to achieve rapid, portable, and visual monitoring of β-LA. Using penicillin G as a model, a detection limit as low as 15.7 nM was achieved, showing important implications for β-LA detection.