Rationally Trapped Polycrystalline Perovskite in Lanthanide MOF Cages for Ammonia-Mediated Nucleic Acid Intelligent...

Perovskites nanoparticles (PNPs), promising materials in fluorescence biosensing, have has their practical applications stymied by poor stability in polar solvents. Integrating PNPs into metal-organic frameworks (MOFs) offers a solution by enhancing their compatibility with various environments. Lanthanide MOFs (Ln-MOFs) are particularly advantageous due to their customizable structure, enhanced stability, and intrinsic fluorescence. Herein, the mechanism by which hybrid materials achieve a balance between physical and fluorescence properties is elucidated. Through theoretical calculations, 2,2'-bipyridine-5,5'-dicarboxylic acid is selected as the ligand to sensitize Eu³⁺ and facilitate Pb²⁺ chemisorption. In addition, 4-bromobutyric acid is not only employed to create hierarchical Eu-MOFs and optimize the framework for in situ growth of polycrystalline perovskites but also utilized to generate zwitterionic ligands through an S_N2 reaction with MOF cages restricted n-octylamine, ensuring the stable dispersion of hybrid materials in ethyl acetate (polar solvent). The prepared PNPs@Ln-MOF exhibits significantly enhanced fluorescence lifetime (50-fold) and stability in polar solvents. Besides, the highly sensitive fluorescence color shift of PNPs@Ln-MOF in response to ammonia offers a generalizable strategy for ammonia-mediated biosensing device. Supported by CRISPR/Cas technology, this device allows for precise on-site nucleic acid assay (LOD = 200 fM), pioneering advanced applications of perovskite-based hybrid materials in biosensing.