An orientation-controlled molecularly imprinted paper-based fluorescent sensor for turn-on detection of ochratoxin A

Detection technologies based on molecularly imprinted polymers (MIPs) have been developed for analyzing ochratoxin A (OTA), a highly toxic food contaminant. However, conventional MIPs suffer from disordered imprinting cavities, which compromise their analytical performance for OTA. Herein, we first proposed a luminescent metal organic framework (LMOF)-based paper-imprinted sensor (FP@Eu-DCBA@MIP) via a dummy template-derivatization-based oriented surface imprinting strategy for efficient OTA analysis. By incorporating a cis-dihydroxy-derived dummy template (OTA-CD) during imprinting, FP@Eu-DCBA@MIP achieved ordered recognition cavities. Compared to the non-imprinted material (FP@Eu-DCBA@NIP), FP@Eu-DCBA@MIP exhibited better adsorption capacity (58.82 mg g^-1) and selectivity (imprinting factor: 3.6) for OTA. The LMOF (Eu-DCBA) served as the detection unit, endowing FP@Eu-DCBA@MIP with good sensitivity for OTA (limit of detection: 0.00352 mg L^-1) through the antenna effect between Eu-DCBA and OTA. The sensor was also successfully applied to OTA analysis in food samples, demonstrating the potential of FP@Eu-DCBA@MIP for OTA detection in complex matrices.