Eriochrome Black T–Eu³⁺ Complex as a Ratiometric Colorimetric and Fluorescent Probe for the Detection of Dipicolinic Acid, a Biomarker of Bacterial Spores

Abstract

A novel ratiometric colorimetric and fluorescent dual probe based on Eriochrome Black T (EBT)-Eu complex was designed to detect dipicolinic acid (DPA), a major constituent of bacterial spores, with high sensitivity and selectivity. UV-vis titration experiments demonstrated that EBT and Eu ions formed a 1:1 coordination pair in water. In the presence of Eu ions, the blue solution of EBT changed to magenta, however, upon the addition of DPA, the magenta color changed to blue immediately and characteristic fluorescence emission from DPA-Eu complex was observed. In addition, the sensitivity of the system was further evaluated on Geobacillus stearothermophilus spores and as low as 2.5 × 10 spores were detected.

Construction of a luminescent square-like Cd6Eu2 nanocluster for the quantitative detection of 2,6-dipicolinic acid as an anthrax biomarker

“…Furthermore, the limit of detection to DPA is obtained as 0.43 μM (LOD = 3 σ / k , 28 where σ is 0.0136 and k is 9.45 × 10 4 ), which is lower than those of some Ln-MOFs and among the lowest ones reported for the fluorescence detection of DPA (Table 1). 9–12,29–34 It is also much lower than the infectious dosage of anthrax spores (60 μM). Compared with the other fluorescent materials, 2 shows a large detection range (Table 1).…”

“…DPA has a unique clamped configuration with the adjacent pyridine nitrogen atom and carboxylate groups, which may help to interact with 2 . 11–14,35 The UV-vis titration of DPA reveals that the absorption peaks of 2 are shifted after the addition of DPA (Fig. S12, ESI†).…”

“…7–10 Some luminescent lanthanide-based metal–organic frameworks (Ln-MOFs) have been used to detect DPA. 11–14 Heterometallic d-4f clusters with metal ions such as Zn 2+ , 15 Cd 2+ , 16 Ru 2+ , 17 Cr 2+ 18 and Pt 2+ 19 may display interesting lanthanide luminescence, since light-absorbing units containing the d-block metals can efficiently sensitize lanthanide emission. However, there are no reports on the use of luminescent high-nuclearity d-4f clusters to detect DPA so far.…”

A ratiometric luminescence nanoprobe based on layered terbium hydroxide nanosheets for quantitative detection of an anthrax biomarker

“…[8][9][10] Anthrax has a microstructure that is highly resistant to extreme environments and can resist environments such as high temperature and high pressure, drought, ultraviolet irradiation, chemical disinfectants, strong acids and alkalis. [11][12][13] Thus, rapid and sensitive detection of Bacillus anthrax is critical for preventing and controlling anthrax disease and bioterrorism. Pyridine-2,6 dicarboxylic acid (DPA) is a major constituent of anthrax spores having a 5-15% dry mass ratio in the spores, 3,6,8,11,12,14 which is not present in other natural and synthetic materials.…”

The role of l-histidine as molecular tongs: a strategy of grasping Tb3+ using ZIF-8 to design sensors for monitoring an anthrax biomarker on-the-spot

“…Therefore the intrinsic fluorescence of Tb 3+ was sensitized, leading to bright yellow green fluorescence owing to the antenna role of DPA. The as-prepared His@ZIF-8/Tb 3+ -based sensing platform possesses the following advantages: (1) the synthesis process was very simple and carried out at room temperature without using highly toxic reagents, such as Eriochrome Black T. 29 (2) The highly uniform nanoscale cavities and large surface area of His@ZIF-8 not only played an important role in specifically identifying targets but also promoted the target enrichment effect in their micro-pores, resulting in a lower detection limit and a higher sensing sensitivity. (3) The strategy used for functionalizing MOFs with natural amino acids to construct sensing probes is very fascinating, and will provide a beneficial reference for the modification of MOFs.…”