AI-powered nanozyme-imprinted fluorescence μPAD sensor for on-site simultaneous visual detection of carbendazim and thiabendazole

Carbendazim (CBZ) and thiabendazole (TBZ), belonging to benzimidazole fungicides, are widely applied in fruit disease control. However, their excessive use is severely threatening toward the ecological environment and human health. Developing a portable and rapid on-site detection method is required. In this study, a dual-mode nanozyme-imprinted fluorescence paper-based microfluidic sensor was developed for the simultaneous detection of CBZ and TBZ. Molecularly imprinted polymers based on the surface of peroxidase-like zeolitic imidazolate framework-67 (RHB@ZIF-67@MIP and r-CDs@ZIF-67@MIP) were respectively constructed by sol-gel method for highly selective recognition of target analytes. These two imprinted nanozymes were respectively assembled onto the paper-based microfluidic (μPAD) sensing platform to form a dual-channel imprinted fluorescence μPAD sensor. A dual-ratiometric fluorescence detection system was constructed by incorporating two distinct chemical reactions, namely the hydrogen peroxide (H₂O₂)/terephthalic acid system and the H₂O₂/o-phenylenediamine system. Integrating with a smartphone and an AI image processing program, fluorescence detection, image acquisition, and real-time analysis toward CBZ and TBZ were completed within 10 min. The RHB@ZIF-67@MIP μPAD sensing zone showed a linear response toward CBZ across 0.001–100 μM. While the r-CDs@ZIF-67@MIP μPAD sensing zone demonstrated effective TBZ detection across 0.005–300 μM. AI-powered rapid processing fluorescence signals enhanced analysis efficiency. The nanozyme-imprinted fluorescence μPAD sensor exhibits high sensitivity, rapid detection, and portability, providing a novel method for rapid on-site detection of benzimidazole pesticide residues.