Chiral Metal–Organic\nFramework Films with Ordered\nMacropores for Enantioselective Analysis of Proteins

Chiral film-based sensors show great promise for discriminating\nbetween enantiomers due to their miniaturization and low power consumption.\nHowever, their practical use is hindered by the trade-off between\nenantioselectivity and mass transfer capability, especially concerning\nbiomacromolecules such as proteins. In this work, we present an effective\nand straightforward method for creating highly organized macropores\nwithin crystalline chiral metal–organic framework (CMOF) films.\nThis approach harnesses the shaping influence of a polystyrene nanosphere\ntemplate and the crystallization induced by the liquid dielectric\nbarrier discharge plasma. The resultant highly ordered macro–microporous\nstructures improve mass diffusion and access to chiral active sites\nin the hierarchical CMOF films. Coupled with their inherent chirality,\nstrong fluorescence emission, high crystallinity, and exceptional\nstability, these attributes endow these CMOF films with enhanced sensing\ncapabilities for chiral molecules. Particularly, the macro–microporous\nstructure facilitates efficient protein recognition, overcoming a\nsignificant challenge encountered by MOFs due to protein dimensions\nsurpassing MOF pore sizes. These films exhibit increased enantioselectivity,\nbetter limits of detection, and wider linear ranges compared with\npurely microporous CMOF films. This study thus provides a powerful\nsynthetic approach for hierarchical CMOF films, addressing the limitations\nof traditional thin film sensors and opening an avenue for efficient\nchiral sensing of large biomacromolecules.