An anionic layered europium(iii) coordination polymer for solvent-dependent selective luminescence sensing of Fe3+ and Cu2+ ions and latent fingerprint detection

A nanomaterial-independent and fluorescent immunoassay based on Eu-micelles for rapid and sensitive detection of fluoroquinolones in chicken

Fluorescent nanoprobes are widely applied in innovate enzyme-linked immunosorbent assays (ELISA) for detection of fluoroquinolones (FQs) residue in foodstuffs. Nevertheless, the complicated synthesis of nanoprobes hampers their practical applications. Herein, a nanomaterial-independent and fluorescent ELISA for sensitive detection of FQs is developed using the Eu-micelles as signal probe. Non-nanostructured Eu-micelles with high quantum yield and stability are facilely synthesized through the assembly of Eu3+ and ligands. Alkaline phosphatase catalyzes hydrolysis of 4-nitrophenyl phosphate to 4-nitrophenol. The fluorescent Eu-micelles can be readily quenched by 4-nitrophenol via static quenching. The signal generation mechanism integrates well with conventional ELISA systems. The established fluorescent ELISA achieves sensitive detection of FQs with a limit of detection of 0.03 μg/kg. The validation results from LC-MS show that the fluorescent ELISA exhibits good accuracy and recoveries. Our study presents a nanomaterial-independent strategy for developing the rapid immunoassay for FQs, which holds good promise for practical applications.

Ultrasound-assisted synthesis of a Eu3+-functionalized ZnII coordination polymer as a fluorescent dual detection probe for highly sensitive recognition of HgII and L-Cys

A new ZnII coordination polymer (CP) based on 2,3-pyrazine dicarboxylic acid (H2pzdc) and 4,4'-bipyridine (bpy) (ZCP) was synthesized using a facile slow evaporation method. Single-crystal X-ray diffraction revealed that ZCP is a two-dimensional porous CP, [Zn2(pzdc)2(bpy)(H2O)2]n, with van der Waals forces as the dominant interaction within its layers forming a 63 network. Employing energetic ultrasound irradiation, nanoscale ZCP (nZCP) was successfully synthesized and Eu3+ ions were incorporated within its host lattice (Eu@nZCP). The resulting platform exhibits superior fluorescence characteristics and demonstrates notable optical durability. Therefore, it was used as a dual detection fluorescent sensing platform for the detection of mercury and L-cysteine (L-Cys) in aqueous media through a turn-off/on strategy. In the turn-off process, the fluorescence emission of Eu@nZCP progressively quenches by the addition of HgII via a photo-induced electron transfer (PET) mechanism. The fluorescence of Eu@nZCP is quenched to establish a low fluorescence background through the incorporation of HgII. This devised turn-on fluorescent system is suitable for the recognition of L-Cys (based on the strong affinity of L-Cys to the HgII ion) through a quencher detachment mechanism. This method attained a relatively wide linear range, spanning from 0.001 to 25 µM, with the low detection limit of 5 nM for the sensing of HgII. Also, the corresponding limit of detection (LOD) for L-Cys is 8 nM in a relatively wide linear range, spanning from 0.001 to 40 µM.

Detection Enhancement of One Multifunctional Cd-Metal-Organic Framework toward Tetracycline Antibiotics by Simply Mixing Eu3+ in Suspension

It is necessary to find more simple methods to improve the detection selectivity and sensitivity of antibiotics. Herein, we constructed a novel three-dimensional (3D) Cd-MOF LCU-117 assembled from p-terphenyl-4,2″,5″,4'-tetracarboxylic acid, which showed a special 3D helical structure with carboxylic acid ligands and nitrogen-containing ligands crossing each other vertically. Luminescence measurements indicated that LCU-117 has high selectivity and sensitivity toward Eu³⁺ through the ratiometric effect. Meanwhile, this complex itself could detect antibiotics oxytetracycline (OTC) through the turn-off mechanism. When Eu³⁺ was added in suspensions of LCU-117 (noted as Eu³⁺@LCU-117), the detection toward OTC was enhanced significantly and visually. The sensing mechanism was investigated in detail by various measurements and theoretical calculations. LCU-117 has a good effect on the logic gate, potential fingerprint detection, and mixed-matrix membranes (MMMs). The practical application for monitoring OTC in water samples also provided a satisfactory result.

Detection of anthrax biomarker and metallic ions in aqueous media using spherical-shaped lanthanide infinite coordination polymers

We report a lanthanide-based infinite coordination polymer (ICP) system synthesized using pyrazole-3,5-dicarboxylic acid as linker, malonic acid as coordination modulator and water as solvent. The precursors self-assembly into microspherical particles, which are water-stable and exhibit excellent dispersibility. Bimetallic samples based on Tb³⁺ doped with Eu³⁺ were investigated as ratiometric dipicolinic acid (DPA) sensors, which is a biomarker for Bacillus anthracis spores. Along with the calibration curves, a detection in a real sample extracted from Bacillus subtilis (model organism) was performed. The samples proved to be highly sensitive and selective for ratiometric DPA detection. In a secondary study, the monometallic sample containing only Tb³⁺ was also investigated as a sensor for ionic species in aqueous media. The Cr³⁺, Fe³⁺, Cu²⁺, and Cr₂O₇^2- ionic species could be detected in water by luminescence quenching mechanism. Therefore, we found that the reported ICP system can be judiciously constructed in order to act as a multimodal probe for several chemical species.

Dye-based dual-emission Eu-MOF synthesized by Post-modification for the sensitive ratio fluorescence visualization sensing of ClO. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023;285:121863. [PMID: 36126623 DOI: 10.1016/j.saa.2022.121863]

As we all know, excessive hypochlorite will be transformed into highly toxic substances, while insufficient hypochlorite can not completely kill bacteria and viruses in water. Therefore, it is desirable to develop a new analytical method to detect ClO^- in environmental water. Here, a novel and simple fluorescence sensor was constructed for monitoring ClO^- by an effective strategy. An Acriflavine@lanthanide metal-organic framework (Acr@Eu(BTEC)) was designed by covalently integrating amino-rich dye (Acr) and carboxyl-rich Eu(BTEC) via post-synthesis method. The created fluorescence sensor has two emission centers originating from Acr and Eu(BTEC), respectively. In the presence of ClO^-, the strong green fluorescence derived from Acr was significantly quenched, while the invariant red emission from Eu³⁺ acted as the reference signal. Thus, Acr@Eu(BTEC) with two emissions was developed as a ratiometric fluorescence sensor for highly sensitive and selective detection of ClO^-. The limit of detection (LOD) was as low as 10.75 nM. Moreover, visual detection of ClO^- by the naked eyes is feasible with obvious fluorescent color changes from green to orange and then red. This method shows excellent performance in practical application, which suggests that it has great potential in water quality monitoring.

Fluorescence Enhancement of Dicyanomethylene-4H-Pyran Derivatives in Solid State for Visualization of Latent Fingerprints

The efficient development of latent fingerprint (LFP) is attractively important for criminal investigation. The low-cost and high-contrast developer is still a challenge. In this study, we designed and synthesized dicyanomethylene-4H-pyran (DCM) derivatives PZ-DCM and Boc-PZ-DCM by introducing of large steric hindrance group Boc, the solid-state fluorescence of DCM derivatives was greatly enhanced. The low-cost fluorescent LFP developers were prepared by blending with different proportion of montmorillonite (MMT). As a result, clear and high contrast fingerprint patterns were obtained with dusting method by the developer with 3% content of Boc-PZ-DCM. Furthermore, we employed the developer with 3% content of Boc-PZ-DCM to develop the sweat latent fingerprints on different substrates by powder dusting, and collected clear fingerprint patterns, indicating that the developer is universal. In a word, the Boc-PZ-DCM/MMT powder is a promising candidate for LFP developer.

A Fluorene based Fluorogenic ''Turn-off'' Chemosensor for the Recognition of Cu2+ and Fe2+: Computational Modeling and Living-cell Application

Background:

The traditional methods for the detection and quantification of Cu2+ and Fe3+ heavy metal ions are usually troublesome in terms of high-cost, non-portable, time-consuming, specialized personnel and complicated tools, so their applications in practical analyses is limited. Therefore, the development of cheap, fast and simple-use techniques/instruments with high sensitivity/selectivity for the detection of heavy metal ions is highly demanded and studied.

Methods:

In this study, a fluorene-based fluorescent 'turn-off' sensor, methyl 2-(2-((((9H-fluoren-9- yl)methoxy)carbonyl)amino)-3- phenylpropanamido) acetate (probe FLPG) was synthesized via onepot reaction and characterized by 1H-NMR, 13C-APT-NMR, HETCOR, ATR-FTIR and elemental analysis in detailed. All emission spectral studies of the probe FLPG have been performed in CH3CN/HEPES (9/1, v/v, pH=7.4) media at rt. The quantum (Φ) yield of probe FLPG decreased considerably in the presence of Cu2+ and Fe3+. The theoretical computation of probe FLPG and its complexes were also performed using density functional theory (DFT). Furthermore, bio-imaging experiments of the probe FLPG was successfully carried out for Cu2+ and Fe3+ monitoring in living-cells.

Results:

The probe FLPG could sense Cu2+ and Fe3+ with high selectivity and sensitivity, and quantitative correlations (R2>0.9000) between the Cu2+/Fe3+ concentrations (0.0−10.0 equiv). The limits of detection for Cu2+ and Fe3+ were found as 25.07 nM and 37.80 nM, respectively. The fluorescence quenching in the sensor is managed by ligand-to-metal charge transfer (LMCT) mechanism. Job’s plot was used to determine the binding stoichiometry (1:2) of the probe FLPG towards Cu2+ and Fe3+. The binding constants with strongly interacting Cu2+ and Fe3+ were determined as 4.56×108 M-2 and 2.02×1010 M-2, respectively, via the fluorescence titration experiments. The outcomes of the computational study supported the fluorescence data. Moreover, the practical application of the probe FLPG was successfully performed for living cells.

Conclusion:

This simple chemosensor system offers a highly selective and sensitive sensing platform for the routine detection of Cu2+ and Fe3+, and it keeps away from the usage of costly and sophisticated analysis systems.

Two coordination polymers as multi-responsive luminescent sensors for the detection of UO22+, Cr(vi), and the NFT antibiotic

Two CPs have been synthesized using solvothermal method and can act as multi-responsive luminescent probe to detect UO22+ cation, Cr2O72−/CrO42− anions, and nitrofuran antibiotic in aqueous media with high sensitivity and selectivity.

Eu-MOF and its mixed-matrix membranes as a fluorescent sensor for quantitative ratiometric pH and folic acid detection, and visible fingerprint identifying

The integration of 1 and polymer matrices leads to the fabrication of 1@polymer MMMs, which can be used in the detection of pH and folic acid. Powder samples of 1 also show potential for application in fingerprint identification.

Assembly of two novel coordination polymers by selecting ditopic or chelating auxiliary ligands with naphthalene-2,6-dicarboxylic acid: synthesis, structure and luminescence sensing

The Fe^III ion as a ubiquitous metal plays a key role in biochemical processes. Iron deficiency or excess in the human body can induce various diseases. Thus, effective detection of the Fe^III ion has been deemed an issue of focus. To develop more crystalline chemical sensors for the selective detection of Fe³⁺, two novel two-dimensional (2D) coordination polymers, namely, poly[[[μ-bis(pyridin-4-yl)amine-κ²N:N'](μ-naphthalene-2,6-dicarboxylato-κ²O²:O⁶)zinc(II)] 0.5-hydrate], {[Zn(C₁₂H₆O₄)(C₁₀H₉N₃)]·0.5H₂O}_n, 1, and poly[(4,4'-dimethyl-2,2'-bipyridine-κ²N,N')(μ-naphthalene-2,6-dicarboxylato-κ²O²:O⁶)hemi(μ-naphthalene-2,6-dicarboxylic acid-κ²O²:O⁶)copper(II)] [Cu(C₁₂H₆O₄)(C₁₂H₁₂N₂)(C₁₂H₈O₄)_0.5]_n, 2, have been prepared using solvothermal methods. Single-crystal X-ray diffraction analysis shows that compound 1 is an undulating twofold interpenetrated 2D (4,4)-sql network and compound 2 is a twofold interpenetrated 2D honeycomb-type network with a (6,3)-hcb topology. In addition, 1 exhibits highly selective sensing for the Fe³⁺ ion.

Interpol review of fingermarks and other body impressions 2016-2019

This review paper covers the forensic-relevant literature in fingerprint and bodily impression sciences from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20 Review%20 Papers%202019. pdf.