Surface-Oriented Assembly of Cyclodextrin Metal-Organic Framework Film for Enhanced Peptide-Enantiomers Sensing

Abstract

Oriented metal-organic framework (MOF) films are attracting great attention due to their fascinating physicochemical properties and unique functionalities. Here, we report an [110]-oriented biomolecular γ-cyclodextrin (γCD) MOF film with arrayed CD channels running perpendicular to the substrate surface. This sophisticated architecturewas realized by combining liquid phase epitaxial layer-by-layer (lbl)methods with a γCD-based thiol self-assembled monolayer (SAM) functionalized surface. This first demonstration of the lbl method for MOF growth from aqueous conditions yielded oriented, highly homogeneous, and chiral γCD-SURMOFs (surfacecoordinated MOFs) with tunable thickness. Using a quartz crystal microbalance (QCM) to monitor adsorption of biomolecules, we demonstrated that γCD-SURMOF provides highly-efficient recognition of tripeptide enantiomers (Tyr-(L-Ala)-Phe vs Tyr- (D-Ala)-Phe), clearly outperforming γCD(SH)8SAMs as well as polycrystalline, mixed-orientations γCDMOF film. The presence of well-aligned γCD-channels enables highly efficient transport channels with large adsorption capacity and fast loading, along with high enantioselectivity. In addition, the fast and highly specific loading rates allow for the realization of highly specific sensors for biomolecules with short response times.