Construction of Molecular Sensing and Logic Systems Based on Site-Occupying Effect-Modulated MOF–DNA Interaction

Interactions between metal–organic frameworks (MOFs) and nucleic acids are of great importance in molecular assembly. However, current MOF–nucleic acid interactions lack diversity and are normally realized in an uncontrollable manner. Herein, the interaction of zirconium-based MOFs (Zr-MOFs) with nucleic acids is enabled by the formation of Zr–O–P bonds and further manipulated by a phosphate-induced site-occupying effect. Covering Zr ions in clusters of MOFs with phosphates impedes the formation of Zr–O–P bonds with nucleic acids, rendering the MOF–nucleic acid interaction tunable and stimulus-responsive. Notably, the experimental results demonstrate that various phosphates, Zr-MOFs, and nucleic acids can all be adopted in the tunable interaction. On the basis of these findings, fluorescent DNA and typical Zr-MOFs are proposed as functional probe–quencher pairs to establish molecular sensing and logic systems. Accordingly, alkaline phosphatase and inorganic pyrophosphatase can be quantified simultaneously, and the overall relation of different phosphates and phosphatases is facilely displayed. The work provides a general strategy for modulating MOF–nucleic acid interactions, which is conducive to the development of molecular intelligent systems.