Breathable Biomimetic Chiral Porous MOF Thin Films for Multiple Enantiomers Sensing

Abstract

Chiral sensing is essential in pharmaceuticals, food safety, and environmental monitoring, but effectively and accurately detecting various enantiomers continues to be a substantial challenge. Inspired by the dynamic conformational change of olfactory receptor proteins, natural L‐carnosine (Car) is used as a ligand to assemble the first highly crystalline and oriented chiral peptide‐based metal‐organic framework (MOF) thin films with liquid‐phase epitaxial layer‐by‐layer approach (named surfac‐coordinated MOF thin films, SURMOFs). By adjusting the solvent environment, these chiral and at the same time porous SURMOFs mimic the conformational flexibility of receptor proteins, exhibiting dynamic structural changes. This “breathing effect” enables ZnCar SURMOFs to selectively sense six fragrance enantiomers, including (+)/(−)‐carvone, (+)/(−)‐menthol, and (+)/(−)‐limonene. By incorporating these films into a quartz crystal microbalance (QCM) and analyzing the frequency shifts using convolutional neural networks (CNN), a highly sensitive gravimetric biomimetic chiral sensor capable of detecting multiple enantiomers has been developed. With a sensitivity range of 10 to 200 ppm, the sensor reached a recognition accuracy of 98.58% for these six enantiomers, showcasing outstanding selectivity and flexibility.