Dual-Emitting Mixed-Lanthanide Metal–Organic Framework for Ratiometric and Quantitative Visual Detection of 2,6-Pyridine Dicarboxylic Acid

Abstract

The detection of the major biomarker of Bacillus anthracis, 2,6-dipicolinic acid (DPA), has attracted great interest in recent years. In this work, mixed-lanthanide metal–organic frameworks (M’LnMOFs), Tb x Eu1–x -cppa (cppa = 5-(5-carboxypyridin-3-yl)isophthalic acid), with different Tb/Eu ratios, were solvothermally synthesized. The results reveal that ratiometric fluorescent probe [Tb0.533Eu0.467-(Hcppa)1.5(H2O)(DMF)]·3H2O is water and acid–base stable and exhibits excellent sensitivity (LOD = 2.286 μM), high selectivity, and fast response (<2 min) for the detection of DPA. Due to the blocked energy transfer from Tb3+ to Eu3+ and the inner filter effect upon the addition of DPA, the fluorescent probe shows a distinct color change from orange-red to green. Furthermore, the visual detection of DPA was realized by identifying the RGB values of MOF-based agarose hydrogel films via a smartphone, highlighting the practical application of the fluorescent probe for DPA detection under aqueous solution conditions.

Two Octa-Nuclear {Ln8} (Ln = Tb, Dy) Complexes with “4 + 4” Covalent Organic Macrocycles: Structure, Solution Behavior, Luminescence, and Magnetic Properties

“…The detection limit of 13.8 nM for the “turns on” fluorescence-sensing behavior was calculated using the rule of 3σ/ K (σ is the standard deviation of 20 groups of blank samples, K is the slope of the fitted curve of y = 7.060 + 9.203 x , with the range of 0.01–35 μM). Compared with other lanthanide compounds used for DPA detection, including a Cd 10 Tb 9 nanocluster with excitation wavelength-dependent detection (0.23 nM), a high-nuclearity Yb 18 nanoring with a detection limit of 1.5 μM and a mixed-lanthanide TbEu-MOFs with a detection limit of 2.286 μM, − this Tb 8 L 4+4 covalent organic macrocycles exhibited good sensitive for the fluorescence detection of DPA. To further discuss the luminescence “turns on” response of Tb 8 L 4+4 to DPA in water, ESI-MS technology had been used for the detection.…”

Ratiometric Lanthanide Metal‐Organic Frameworks (MOFs) for Smartphone‐Assisted Visual Detection of Food Contaminants and Water: A Review

“…Most recently, Q. Wang and colleagues introduced a novel dual-emitting mixed-lanthanide MOF for ratiometric and quantitative visual detection of 2,6-Pyridine dicarboxylic acid (DPA) [125] in water. This innovation, illustrated in Figure 10, brought forth intriguing findings.…”

Paper-Based Microfluidic Sensors Utilizing Metal–Organic Framework Materials Modified with Europium and Carbon Quantum Dots for Anthrax Spore Biomarker Detection

“…4 Currently, the potential threat posed by spores has garnered increasing attention in the realm of health and safety, 2,5 6-pyridinedicarboxylic acid (DPA) constitutes the primary component of the spore protective layer, representing approximately 5−15% of the spore's dry mass. 6 DPA serves as a crucial biomarker for spores. Consequently, the development of a portable, rapid, and sensitive sensor for detecting this spore biomarker holds immense significance for human health, the food industry, and national security.…”

“…It has the capability to remain dormant and regenerate under favorable environmental conditions . Currently, the potential threat posed by spores has garnered increasing attention in the realm of health and safety, , 6-pyridinedicarboxylic acid (DPA) constitutes the primary component of the spore protective layer, representing approximately 5–15% of the spore’s dry mass . DPA serves as a crucial biomarker for spores.…”