Aptamer-functionalized metal-covalent organic framework as nanofluidic sensor for ultrasensitive and selective...

Patulin contamination constitutes a persistent threat to food safety systems, environmental sustainability and public health protection. The development of highly selective and sensitive analytical method for the detection of trace patulin in complex food matrices is essential to safeguarding public health. Herein, we show a novel metal-covalent organic frameworks (MCOF) biomimetic nanofluidic sensor for the detection of trace patulin in complex food matrices. The nanofluidic sensor was fabricated via in situ growth of aptamer-functionalized gold-covalent organic framework (Au-COF) on anodic aluminum oxide (AAO) nanochannels. The introduction of MCOF into the design of nanofluidic sensors not only provides confined effect of COF nanochannels, but also offers additional abundant active metal sites for efficient immobilization of aptamer to achieve signal amplification and selectivity improvement. The integrated nanocomposite was characterized by scanning electron microscopy, Fourier transform infrared, powder X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential measurements and Raman spectroscopy. The developed nanofluidic sensor exhibited a wider linear range from 50 pg L^-1 to 1000 ng L^-1, low detection limit of 3.83 pg L^-1, and quantitative recovery from 88.4 % to 104 % in real-world food matrices. The proposed aptamer-functionalized MCOF nanofluidic system provides a promising nanoplatform for the design of nanofluidic sensors for selective and ultrasensitive detection of trace analytes in complex matrices.