Exploiting Aptamer-Modulated Interfacial Effects of Metal-Organic Framework-Derived Nanozymes for Specific Colorimetric Sensing of Histamine

Nanozymes hold promise for mimicking the biocatalytic functions of natural enzymes, but their applications are restricted due to their poor catalytic selectivity. Aptamers (Apt), as functional nucleic acids, can selectively bind to targets. Their integration can readily confer specificity to nanozymes, which is suitable for the construction of highly specific sensors. However, the underlying mechanism of the sensors primarily involving the interface interaction between Apt, nanozymes, and analytes is still unclear. In this study, a metal-organic framework (MOF)-derived peroxidase-like nanozyme (Pd/Pt@UiO66-NH₂) colorimetric aptamer sensor has been constructed for selective, accurate, and rapid detection of a classic biogenic amine (histamine, HA). How the specific binding of HA to Apt further affects the surface-interface effect between Apt and nanozymes has been thoroughly investigated. The results indicated that the catalytic activity of Pd/Pt@UiO66-NH₂ nanozymes is modulated by Apt with local coordination and hydrogen bonds and is further inhibited by the target analyte competing with the chromatic substance for reactive oxygen species (ROS) on the nanozyme surface. Additionally, the sensor is demonstrated to show high selectivity, high accuracy, and an ultrawide detection range (0.045-89.97 μM) with a calculated limit of detection (3.6 nM). The surface interfacial interactions between aptamer-mediated nanozymes offer unique insight for constructing efficient colorimetric sensing strategies.