Lab-on-MOFs: Color-Coded Multitarget Fluorescence Detection with White-Light Emitting Metal–Organic Frameworks under Single Wavelength Excitation

Abstract

Multitarget assay with single detection modality from individual stimulation mode has aroused great attention. Here, we realize multitarget detection with the color change as signal source from single white light-emitting metal-organic frameworks (MOFs) under single wavelength excitation for the first time. The white light-emitting MOFs are prepared by carefully tuning the ratio of Eu³⁺, Tb³⁺, and Dy³⁺ ions to obtain trimetal MOFs; 5-boronoisophthalic acid (5-bop) provides additional selectivity as ligand. Based on antenna effect, 5-bop is excited to produce its triplet-state, which sensitizes the Ln³⁺ ions for the white emission. Thus, all of the fluorescence emission is achieved under single wavelength excitation at 275 nm, while any factors affecting the procedure result in the modulation of emission for diverse wavelengths. The trimetal MOFs display distinctive emission colors after interacting with different targets, including metal ions, anions, small molecule, and even biomolecule as a Lab-on-MOFs system. This system shows higher integration degree and simpler preparation and sensing procedures than other multitarget detection strategies.