Ultra-stable MAPbBr3@ZIF-8-based fluorescent aptasensor for highly sensitive and specific detection of azlocillin in food

Sensitive and selective determination of azlocillin (Azl) is of great significance to food safety and human health as it is recognized as the most prevalently utilized (3-lactam antibiotics. Herein, we develop a highly sensitive fluorescence aptasensor selective, and sensitive, determination of Azl in food samples. Initially, the aptamer A-58 with the highest affinity(Kd = 64.5 +/- 7.2 nM)was obtained by means of truncation. Subsequently, a highly stable aqueous dispersed perovskite nanocrystal MAPbBr3@ZIF-8 was synthesized and used as a fluorescent marker in aptasensors. The aptasensor was constructed by using MAPbBr3@ZIF-8 as the fluorescence signal source, aptamers as the specific recognition molecules, and AuNPs as a quenching agent. This design integrates the excellent optical properties of perovskite, the fluorescence quenching ability of AuNPs and the specificity of aptamer, exhibiting great promising for trace analysis of Azl in food samples. Under the optimal experimental conditions, the linear detection range of the developed aptasensor method spans from 0.1 to 100 ng/mL, with a detection limit of 0.025 ng/mL. The developed MAPbBr3@ZIF-8 based aptasensor has been effectively utilized for the quantification of azlocillin in milk, demonstrating significant potential in the realm of antibiotic detection.