Brightly Luminescent AIEgens-Based Layered Lanthanide Organic Frameworks: Photoresponsive Formic Acid Vapor Sensing, Intracellular Lysosome Imaging, and Photocatalytic Wastewater Treatment

In this study, a series of multifunctional lanthanide metal–organic frameworks (Ln-PTTA-MOFs) were constructed by assembling the classic aggregation-induced emission (AIE) ligand H 4 PTTA with lanthanide ions. These materials demonstrate three distinct functions: sensing low-concentration formic acid vapor, lysosome imaging in living cells, and photocatalytic wastewater purification. Specifically, the Ln-PTTA-MOFs feature a layered network structure formed by the alternating linkage of H 4 PTTA ligands and LnO 8 . Among them, Eu-PTTA-MOF exhibits a highly selective and visually perceptible optical response to low-concentration formic acid vapor, achieving a detection limit as low as 3.1 ppm. Notably, the highly luminescent, nanoscale Eu-PTTA-MOF enables high-resolution optical imaging of various cancer cells. Co-localization analysis reveals that Eu-PTTA-MOF nanosheets efficiently localize within the lysosomes of living cells, with a colocalization coefficient exceeding 0.93. By leveraging the heavy-atom effect of the lanthanide ions within the SBUs and the high molar extinction coefficient of the organic ligands, the Ln-PTTA-MOFs can generate a “reactive oxygen species storm” even under low-power light irradiation. Consequently, they exhibit excellent photocatalytic degradation performance against organic dyes and antibiotics. This work paves a new way for the design of multifunctional lanthanide metal–organic frameworks that integrate luminescent sensing, bioimaging, and photocatalytic degradation capabilities.