Porous covalent architecture-involved luminescent smart hydrogel with target-responsive framework for signal-amplified inspection of aflatoxin B1.

Robust detection techniques combined with functional micro-/nano-entities can be an ideal solution for food-safety risk treatment related to aflatoxin B1 (AFB1). In this work, a porous covalent architecture-involved luminescent smart hydrogel with dynamic cross-linking and target-responsive framework was prepared for specific determination of AFB1 with remarkable sensitivity. Different from the existing hydrogel probe, the introduction of covalent organic frameworks (COFs) enhanced the hydrophobicity of hydrogel, enabling the selective capture of AFB1 with improved affinity while excluding large matrix molecules, thus creating an anti-interference detection environment. Additionally, the pH-responsive carbon dots (CDs) embedded in the smart hydrogel contributed to a dual signal amplification, induced by deconstruction of hydrogel to release the CDs and urease-catalyzed hydrolysis reaction to increase the pH, when the AFB1 presented. In view of this signal amplification and trace enrichment strategy, this smart hydrogel can achieve robust determination of AFB1 with a detection limit of 0.03 µM as well as good specificity. The method was validated using real-world samples, demonstrating excellent accuracy and precision compared to standard HPLC methods. This work not only advances the field of AFB1 detection but also provides a versatile and cost-effective platform that can be adapted for the detection of other toxins and biomolecules, addressing global food safety and environmental monitoring challenges.