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Dipicolinic acid (DPA), as a biomarker for Bacillus anthracis, is highly toxic at trace levels. Rapid and on-site quantitative detection of DPA is essential for maintaining food safety and public health. This work develops a dual-channel self-calibrated fluorescence sensor constructed by the YVO 4 :Eu and Tb-β-diketone complex for rapid visual detection of DPA. This sensor exhibits high selectivity, fast response time, excellent detection sensitivity, and the detection limit is as low as 4.5 nM in the linear range of 0-16 μM. A smartphone APP and portable ultraviolet lamp can assemble a mobile fluorescence sensor for on-site analysis. Interestingly, adding Cu 2+ ions can quench the fluorescence intensity of Tb 3+ . In contrast, the addition of cysteine can restore the fluorescence, allowing the accurate detection of Cu 2+ ions and cysteine in environmental water and food samples. This work provides a portable sensor that facilitates real-time analysis of multiple targets in food and the environment., Competing Interests: Declaration of competing interest The authors state that they have no known competing financial interests or personal relationships, which may affect the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Anthrax bacillus is a very dangerous zoonotic pathogen that seriously endangers public health. Rapid and accurate qualitative and quantitative detection of its biomarkers, 2,6-dipicolinic acid (DPA), is crucial for the prevention and treatment of this pathogenic bacterium. In this work, a novel Cd-based MOF (TTCA-Cd) has been synthesized from a polycarboxylate ligand, [1,1':2',1″-terphenyl]-4,4',4″,5'-tetracarboxylic acid (H 4 TTCA), and further doped with Tb(III), forming a dual-emission lanthanide-functionalized MOF hybrid (TTCA-Cd@Tb). TTCA-Cd@Tb can be developed as a high-performance ratiometric fluorescent sensor toward DPA with a very low detection limit of 7.14 nM and high selectivity in a wide detection range of 0-200 μM, demonstrating a big advancement and providing a new option for the detection of DPA.

Development of reliable methods for the detection of potential biomarkers is of the utmost importance for an early diagnosis of critical diseases and disorders. In this study, a novel lanthanide-functionalized carbon dot-based fluorescent probe Zn-CD@Eu is reported for the ratiometric detection of dipicolinic acid (DPA) and uric acid (UA). The Zn-CD@Eu nanoprobe was obtained from a simple room-temperature reaction of zinc-doped carbon dots (Zn-CD) and the EDTA-Eu lanthanide complex. Under optimal conditions, a good linear response was obtained for DPA in two concentration ranges of 0-55 and 55-100 μM with a limit of detection of 0.53 and 2.2 μM respectively, which is significantly below the infectious dosage of anthrax (∼55 μM). Furthermore, the Zn-CD@Eu/DPA system was employed for the detection of UA with a detection limit of 0.36 μM in the linear range of 0-100 μM. The fluorescent probe was successfully implemented for determining DPA and UA in human blood serum, sweat, and natural water bodies with considerable recovery rates. In addition, the potential of the nanoprobe for ex vivo visualization of UA was demonstrated in fruit fly ( Drosophila melanogaster ) as a model organism.

2,6-Pyridinedicarboxylic acid (DPA) is a significant biomarker of anthrax, which is a deadly infectious disease for human beings. However, the development of a convenient anthrax detection method is still a challenge. Herein, we report a novel europium metal-organic framework (Eu-MOF) with an enhanced peroxidase-like activity and fluorescence property for DPA detection. The Eu-MOF was one-step synthesized using Eu 3+ ions and 2-methylimidazole. In the presence of DPA, the intrinsic fluorescence of Eu 3+ ions is sensitized, the fluorescence intensity linearly increases with an increase in DPA concentration, and the fluorescence color changes from blue to purple. Simultaneously, the peroxide-like activity of the Eu-MOF is enhanced by DPA, which can promote the oxidation of TMB to oxTMB. The absorbance values increase linearly with DPA concentrations, and the colorimetric images change from colorless to blue. The dual-mode detection of DPA has good sensitivity with a colorimetric detection limit of 0.67 μM and a fluorescent detection limit of 16.67 nM. Moreover, a simple detection method for DPA was developed using a smartphone with the RGB analysis system. A portable kit with standard color cards was developed using paper test strips. The proposed methods have good practicability for DPA detection in real samples. In conclusion, the developed Eu-MOF biosensor offers a valuable and general platform for anthrax diagnosis.

Analysis of the dipicolinic acid (DPA) released from Clostridium botulinum spores during thermal processing is crucial to obtaining a mechanistic understanding of the factors involved in spore heat resistance and related food safety applications. Here, we developed a novel mixed-mode liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection of the DPA released from C. botulinum type A, nonproteolytic types B and F strains, and nonpathogenic surrogate Clostridium sporogenes PA3679 spores. DPA was retained on a mixed-mode C18/anion exchange column and was detected using electrospray ionization (ESI) positive mode within a 4-min analysis time. The intraday and interday precision (%CV) was 1.94-3.46% and 4.04-8.28%, respectively. Matrix effects were minimal across proteolytic type A Giorgio-A, nonproteolytic types QC-B and 202-F, and C. sporogenes PA3679 spore suspensions (90.1-114% of spiked DPA concentrations). DPA recovery in carrot juice and beef broth ranged from 105 to 118%, indicating limited matrix effects of these food products. Experiments that assessed the DPA released from Giorgio-A spores over the course of a 5-min thermal treatment at 108 °C found a significant correlation (R = 0.907; P < 0.05) between the log reduction of spores and amount of DPA released. This mixed-mode LC-MS/MS method provides a means for rapid detection of DPA released from C. botulinum spores during thermal processing and has the potential to be used for experiments in the field of food safety that assess the thermal resistance characteristics of various C. botulinum spore types., (© 2022. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Dipicolinic acid (DPA) is an anthrax biomarker. Its serious consequences make its detection a great need. In this paper, three novel metal-organic frameworks (MOFs) with different coordination modes were synthesized by a simple solvothermal method, which can be used as highly efficient fluorescence sensors for the highly selective and sensitive trace detection of DPA. MOFs 1-3 showed rapid responses to DPA (<30 s), and the limits of detection (LODs) were calculated to be 1.01 × 10 -6 M -1 (MOF 1), 1.17 × 10 -6 M -1 (MOF 2) and 2.07 × 10 -6 M -1 (MOF 3). DPA detection based on MOFs 1-3 in fetal bovine serum is highly reliable based on the high recovery rates (90% to 115%). Hence, the three MOF-based sensors can be used in the real-time detection of DPA.

An 18-metal lanthanide nanoring [Yb 18 (L 1 ) 8 (HL 2 ) 2 (OAc) 20 (MeOH) 8 (EtOH) 6 (H 2 O) 4 ] (1), which shows a ratiometric fluorescent response to DPA, was constructed through the strategy of using two types of polydentate organic ligands. The addition of DPA increases the visible ligand-centered emission, but decreases the NIR lanthanide luminescence of 1. The limit of luminescent detection of 1 for DPA is 1.5 μM. The high fluorescence sensitivity of 1 to DPA is not affected by the existence of interferents such as aromatic carboxylates and ions.

One 18-metal Eu(iii) nanoring (size: 1.0 × 2.7 × 2.7 nm) was constructed as a rapid ratiometric fluorescent probe for the detection of dipicolinic acid with high sensitivity and selectivity, by using two types of polydentate organic ligands.

Mixed monolayer-protected gold nanoparticles containing surface-bound triethylene glycol and dipicolylamine groups aggregated in water/methanol, 1 : 2 (v/v) in the presence of nucleotides, if the solution also contained zinc(ii) nitrate to convert the dipicolylamine units into the corresponding zinc complexes. Nanoparticle aggregation could be followed with the naked eye by the colour change of the solution from red to purple followed by nanoparticle precipitation. The sensitivity was highest for adenosine triphosphate (ATP), which could be detected at concentrations >10 μM, and decreased over adenosine diphosphate (ADP) to adenosine monophosphate (AMP), consistent with the typically higher affinity of zinc(ii)-dipicolylamine-derived receptors for higher charged nucleotides. Inorganic sodium diphosphate and triphosphate interfered in the assay by also inducing nanoparticle aggregation. However, while the nucleotide-induced aggregates persisted even at higher analyte concentrations, the nanoparticles that were precipitated with inorganic salts redissolved again when the salt concentration was increased. The thus resulting solutions retained their ability to respond to nucleotides, but they now preferentially responded to AMP. Accordingly, AMP could be sensed selectively at concentrations ≥50 μM in an aqueous environment, even in the presence of other nucleotides and inorganic anions. This work thus introduces a novel approach for the sensing of a nucleotide that is often the most difficult analyte to detect with other assays.

Bacillus anthracis is an extremely dangerous bacterium that is associated with high morbidity and mortality. 2,6-Pyridine dicarboxylic acid (DPA) is a major biomarker of Bacillus anthracis, and it is of great significance to be able to detect DPA in a rapid, efficient, and sensitive way. Herein, a 3D network metal-organic framework (Tb-MOF) with excellent thermal and water stability was synthesized. Tb-MOF could be used to selectively detect DPA via green fluorescence recovery with a fluorescence intensity enhancement factor of 103. In addition, due to the high detection sensitivity (a detection limit of 2.4 μM) and excellent anti-interference abilities, Tb-MOF was less affected by environmental factors when compared with a "turn-off"-response luminescence sensor; it can be employed as a promising "turn-on" luminescence sensor for DPA in the future. Finally, quantum calculations showed that a large energy difference appeared between the 5D4 level of Tb3+ and the first excited triplet energy level of H2-DHBDC2-, which was the reason that the complex did not show characteristic Tb3+ emission.

A ratiometric fluorescence assay was designed for determination of dipicolinic acid (DPA), a spore-specific compound which is used as a biomarker for Bacillus anthracis spores for food and medical product safety analysis. The dual-channel fluorescence probe integrates two fluorescent materials, Eu 3+ ion and gold nanocluster (Au NC). The Au NC is used as a reference channel to measure background noise and the Eu 3+ ion as the DPA-specific response signal channel. The probe was prepared through simply combing bovine serum albumin (BSA)-scaffolded Eu 3+ ion and Au NCs. When excited at 530 nm, in the presence of DPA, the fluorescence signals of Eu 3+ ion at 595, 617, and 695 nm increased significantly while the 650 nm signal of Au NC reference remained relatively constant. This fluorescence probe has good photo-stability and also displays good selectivity and high sensitivity for DPA with a low detection limit of 0.8 μM. The linear range of the ratiometric probe for DPA is 1-50 μM. For determination of DPA released during the germination of Bacillus subtilis spores, the detection results were in agreement with measurements by conventional calorimetry assay. The method may have potential for measuring the level of contamination and germination by spores. Graphical Abstract Dual-channel fluorescence biosensor was designed to detect dipicolinic acid, a spore-specific compound which is used as a biomarker for Bacillus anthracis spores for food and medical product safety analysis.

Composting of beef cattle manure using sawdust or recycled compost as a bulking agent was investigated for the management of clopyralid risk, such as changes in the clopyralid concentration and the mechanism of clopyralid accumulation caused by recycled compost. These raw materials were composted with laboratory equipment, which was controlled at 60℃ after the temperature peak by autothermal composting. Clopyralid concentration did not changed during composting in the thermophilic phase; on the contrary, it increased because clopyralid accumulated in compost when recycled compost was used repeatedly as a bulking agent. The clopyralid accumulation ratio (ratio of clopyralid concentration to that in the first compost) could be explained by a model using a recurrence formula, and a correlation existed between the calculated (model) accumulation ratios and measured accumulation ratios (R 2  = 0.78). Using this model, the excessive accumulation of clopyralid could be controlled when using recycled compost as a bulking agent with lower moisture content or when part of the recycled compost was replaced by another bulking agent, even if recycled compost had high moisture content. In future work, the model and its considerations should be verified in a field test., (© 2021 Japanese Society of Animal Science.)

Dipicolinic acid (DPA) is employed as a significant biomarker to detect Bacillus anthracis, which can do serious damages to the health of human beings. Hence, it is crucial to develop a fast and highly efficient strategy for DPA monitoring. In this work, based on silicon nanoparticles (Si NPs) and terbium metal-organic frameworks (Tb-MOFs), a hybrid structure (Si NPs/Tb-MOFs) as a novel dual-emitting fluorescence probe was fabricated for ratiometric detection of DPA, where blue light-emitting Si NPs (Ex: 280 nm; Em: 422 nm) are encapsulated into green light-emitting Tb-MOFs (Ex: 280 nm; Em: 547 nm). The optical properties and chemical composition of the as-obtained Si NPs/Tb-MOFs were characterized in detail. The Si NPs/Tb-MOFs probe not merely possesses the merits of a facile synthesis method but also is an excellent fluorescence probe. The response time towards DPA is less than 30 s, revealing that the process of detecting DPA can be completed in such a short time. The limit of detection for DPA is 5.3 nM, which is four orders of magnitude lower than an infectious dosage of anthrax spores for human beings (60 μM). This dual-emitting Si NPs/Tb-MOFs probe with interference-free and self-calibrating properties may be a potential candidate for further development in medical diagnosis. Graphical abstract.

In this work, by fully exploring the stimulus response of infinite coordination polymer nanoparticles (ICPs) and by taking advantage of the particular optical properties of ICP guest tetra(4-sulfophenyl)ethene (TPE-TS) with adjustable monomer emission (ME) and aggregation-induced emission (AIE), we demonstrated a novel sensing mechanism for an anthrax biomarker dipicolinic acid (DPA) based on the competitive coordination interaction regulating the structure of TPE-TS@Eu/GMP ICPs. The double ratiometric fluorescence stemmed from triple response of TPE-TS@Eu/GMP ICPs without spectral cross-interference (ME and AIE from TPE-TS and sensitized emission from Eu/DPA) and a corresponding blue-to-red fluorescent color change, which not only benefited the direct detection of DPA with high sensitivity and selectivity, but also offered a great opportunity to realize real-time monitoring of DPA released by Bacillus subtilis spores. Furthermore, the coffee ring deposition patterns on a test paper were innovatively tuned by the quantity and morphology changes of TPE-TS@Eu/GMP ICPs during their stimulus response toward DPA, which could be exploited as expanded signal channels. By integrating a multichannel responsive coffee ring test kit with image recognition and processing application installed on smartphones, point-of-use analysis of DPA could be realized in a low-cost and high-throughput fashion.

In this study, we reported a facile, one-pot, and "green" synthesis of glutathione-protected gold nanoclusters (GSH@AuNCs) initiated by samarium (Sm 3+ ) lanthanides for the first time. Sm 3+ lanthanides more efficiently induced the formation of GSH@AuNCs with significantly enhanced luminescence than other lanthanides or heavy metal ions (Cd 2+ , Pb 2+ ) did. Using this strategy, a detection for Sm 3+ was made with a linearity range of (10.0-100.0 μM) and a limit of detection (LOD) of 0.5 μM. The Sm 3+ -based GSH@AuNCs were characterized by eco-friendliness, photostability, and low-cost synthesis with low biological toxicity and had great potential in the application for biosensing and bioimaging. They were successfully employed in the detection of dipicolinic acid (DPA), a well-reported biomarker for sensing potential infection by strongly hazardous anthrax spores. A good linear response was obtained for DPA detection ranging from 1.0 to 120.0 μM with a low LOD of 0.1 μM, which was much lower (600 times) than the infectious dosage of anthrax spores (6 × 10 -5 M). The detection was due to the strong binding affinity and strong chelation capability of DPA to Sm 3+ lanthanides, which caused the dissociation of the aggregates with an obvious decrease or even a turning-off effect of their luminescence.

Highly selective detection of Bacillus anthrax spores has attracted worldwide attention because Bacillus anthrax spores not only are harmful to the health of human beings and animals, but also can be used as biological warfare agents. Here, we report a simple platform by mixing EuCl 3 ·6H 2 O and sodium polyacrylate in aqueous solution and further investigate its luminescence response towards Bacillus anthrax biomarker dipicolinic acid (DPA) as a turn-on luminescence probe. Importantly, our probe has good sensitivity, lower detection limit, excellent selectivity as well as great anti-interference ability due to the great luminescence enhancement of Eu 3+ . Moreover, a test paper is constructed to realize the purpose of portable detection. These results indicate that our probe is an excellent candidate for sensing DPA., (© 2020 John Wiley & Sons, Ltd.)

Monitoring and early warning of spores germination is of great significance in avoiding their potential pathogenicity. Thus, effective monitoring of markers during spore germination is of great value. A ratio-dependent fluorescent probe based on in situ incorporation of fluorophores in a metal-organic framework (MOF) was designed to monitor a main component of bacterial spores, 2,6-pyridinedicarboxylic acid (DPA), with high sensitivity and specificity. The fluorescence of CdS quantum dots loaded on zeolitic imidazolate framework-8 (ZIF-8) nanocrystals is initially quenched by europium ions. The europium ions, however, can be seized by DPA, leading to restoring the fluorescence of quantum dots. Simultaneously, the fluorescence of another dye molecule, rhodamine 6G, loaded on the ZIF-8 is not affected by DPA and can serve as a stable internal fluorescence reference signal. On this basis, a ratio-dependent fluorescence method for rapid detection of DPA was established. The linear calibration ranged from 0.1 to 150 μM with a detection limit of 67 nM, which is much lower than the amount of DPA (60 μM) released by the contagious number of spores needed to cause anthrax. This analysis platform exhibits good anti-interference ability for monitoring spore germination. The practicable application of the method was verified by monitoring and imaging the release of DPA in the course of spore germination.

A fluorescence off-on sensing platform was developed based on thioglycolic acid-stabilized cadmium sulfide quantum dots (CdS QDs) as fluorescence probe for the sensitive and selective detection of 2,6-pyridinedicarboxylic acid (DPA) in spores. The fluorescence emission intensity of the quantum dots at 650 nm when excited at 460 nm was first quenched by mixing with europium ions (Eu 3+ ) and then recovered after the addition of DPA. The interaction of DPA with Eu 3+ relieved the quenching effect of Eu 3+ toward CdS QDs. As the DPA concentration increases, the color of the probe changes from colorless to red. The method exhibits a wide linear range from 1 to 120 μM for DPA determination, with a detection limit of 0.2 μM. The CdS QDs based nanoprobe was successfully applied for sensitive determination of DPA released from bacteria spores. In this case, the detection limit is 3.5 × 10 4  CFU·mL -1 . Graphical abstract An off-on fluorescence sensor for detecting anthrax markers -2,6-pyridinedicarboxylic acid though restoring the fluorescence of cadmium sulfide quantum dots quenching by europium ions.

The development of novel 2D materials, due to the promising applications they have enabled through their unique properties, has attracted increasingly more research interest. In this regard, novel dual-emitting coordination polymer nanosheets were developed by doping Eu 3+ and Tb 3+ ions into the nanostructures of the [Ba(DPA) 2 (H 2 O) 2 ] n (DPA = dipicolinic acid) coordination polymer (BCP). Single crystal x-ray crystallography revealed that BCP is a 1D coordination polymer and its three-dimensional supramolecular architecture is constructed with a relatively strong hydrogen bonding in the ac crystallographic plane and weak non-covalent interactions along the b axis. Using energetic ultrasound irradiations, synthesis of nanoscale BCP along with the unzipping of the weak interactions between the ac layers was accomplished. The resulting BCP nanosheets was used as the host lattice and was doped with Eu 3+ and Tb 3+ ions. Remarkably, the sensing ability of both Eu 3+ and Tb 3+ doped coordination polymer (Ln@BCP) nanosheets towards temperature and the DPA anthrax biomarker were investigate. The high relative sensitivity value of 2.42% K -1 and their reusability, makes Ln@BCP nanosheets an ideal candidate for the nanothermometry. They also exhibited high selective detection characteristics towards the DPA anthrax biomarker with a 0.03 nM detection limit. Therefore, Ln@BCP nanosheets can also be considered as an efficient multi-responsive optical sensor.

Bacillus anthracis spores have a unique biomarker of calcium dipicolinate (CaDPA). In this work, we reported a composite nanostructure for the optical sensing of DPA, with Eu (III)-doped metal-organic framework (MOF) as supporting lattice, a rhodamine-derived dye as sensing probe, respectively. By means of XRD, IR, TGA and photophysical analysis, this composite structure was carefully discussed. It was found that rhodamine absorption and emission were enhanced by DPA, while Eu emission was quenched by DPA. As a consequence, two sensing skills were observed from this composite structure, which are colorimetric sensing based on absorption spectra and ratiometric fluorescent sensing based on emission spectra. Linear sensing response was observed for both sensing channels with a warning signal at DPA concentration higher than 140 μM. Good selectivity was confirmed with a low LOD value of 0.52 μM. The sensing mechanism was revealed as the combination of emission turn-on effect triggered by DPA-released protons and emission turn-off effect originated from electron-transfer from EuBTC to DPA. This composite structure showed its advantage of naked eye detection and two sensing skills with linear response., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The rapid and sensitive visualization of 2,6-dipicolinic acid (DPA, a unique anthrax biomarker) is essential to prevent anthrax disease or biological terrorist attack. In this study, a Eu 3+ -labeled ethylenediaminetetraacetic acid loaded hyperbranched polyethyleneimine carbon nanodot (hPEI-CD-EDTA-Eu 3+ ) nanoprobe has been proposed for the ratiometric DPA detection. The sensing mechanism is based on the rapid DPA-Eu 3+ chelation within 30 s and subsequent enhanced fluorescence emission through the antenna effect. With the introduction of EDTA chelating unit, the resulted fluorescence of Eu 3+ -complex is greatly enhanced, which endows sensitive DPA perception. By employing hPEI-CD as the internal reference, ratiometric DPA sensing is realized with a good linearity in the concentration range from 1.0 to 100 nM, with a limit of detection of 190 pM (S/N = 3). The specific chelation affinity between Eu 3+ and DPA provides satisfying selectivity over other amino acids and ions. Using nanoprobe-loaded polyvinylidene fluoride paper as the analytical device, point-of-care DPA visualization is achieved. Furthermore, the practical application of designed paper device is validated by the visual detection of metabolic DPA-release from Bacillus subtilis spores., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Terbium(III)-functionalized zirconium-based MOFs (Tb 3+ @UIO-67) were synthesized by doping Tb 3+ into UIO-67 using a post-synthetic modification. The Tb 3+ @UIO-67 (solid or aqueous dispersion) shows only blue fluorescence (emission peaks at 420 nm) under an ultraviolet lamp (254 nm). Upon addition of 2,6-pyridinedicarboxylic acid (DPA; an anthrax biomarker), the color of the Tb 3+ @UIO-67 aqueous dispersion under an ultraviolet lamp changes from blue to green. This is mainly because DPA has a good sensitization effect on Tb 3+ . DPA can be determined by measurement of the ratio of the fluorescence intensities at 544 nm and 420 nm (excitation at 278 nm). The method allows DPA to be detected in the 0.3 to 6 μM concentration range, with a detection limit of 36 nM. Graphical abstract Schematic representation of a ratiometric fluorescent probe synthesized by doping terbium ions into a zirconium-based MOF (UIO-67) for determination of an anthrax biomarker.

In this study, we show that phosphate decreases the spore heat resistance by accelerating the rate of loss of cations from spores. Heat resistance of spores of Geobacillus stearothermophilus A1, D1, P3 and ATCC 12980 were determined in distilled water containing varying concentrations (0.1, 1 and 2% w/v) of di‑sodium phosphate. The average decimal reduction times (D value) for strains A1, D1, P3 and ATCC 12980 in distilled water were 5.8, 6.8, 5.7 and 9 min at 110 °C respectively. On the addition of 0.1, 1 and 2% w/v of di‑sodium phosphate, the average D 110 values of all the strains in distilled water were lowered by 50, 61 and 70% respectively. Addition of 0.05% w/v of Na-EDTA to distilled water resulted in lowering of the average D 110 value of all the strains by 55%. Heat resistance of spores of A1, D1, P3 and ATCC 12980 was found to be associated with the Dipicolinic Acid (DPA) content whose concentrations were 0.25, 0.30, 0.27 and 1.6 pg per spore respectively. Analysis by atomic absorption spectroscopy revealed that the phosphate present in the heating medium causes excess release of calcium from spores with 2% w/v phosphate being highly effective, thus confirming the chelating effect of phosphate. This study provides insight into the heat resistance and the increased heat sensitivity of spores of G. stearothermophilus A1, D1 and P3 in the presence of phosphate, which can be used in the design of Cleaning in Place (CIP) systems involving phosphate based cleaning agents to combat biofilms and spores in the dairy industry., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Anthrax spores have been a determining risk to human beings and animals across the world. As such, the qualitative monitoring toward dipicolinic acid (DPA), the unique biomarker of bacillus anthracis, is highly desired and being moved forward in health management. Herein, a breathing zeolite-like supramolecular assembly (ZSA), with the sra topology and 1D hexagon channel, is designed by controlling the bridging angle of the ditopic ligand after systematic analysis in topology. The solvent-dependent dynamic behavior is illustrated by powder X-ray diffraction and reflected in tunable luminescent emission based on solvent polarity parameters. According to the structural result and theoretical analysis, Eu 3+ is anchored within the framework to form a ratiometric luminescent sensor successfully because of the abundant potential active site. After DPA addition, the resulting composite shows a sensitive and selective response in the linear range of 0-7.0 μM stemmed from absorbance energy-transfer emission and preferential coordination. The work we presented here may enrich the sensing platforms containing lanthanides and expand the potential application of ZSAs in clinical analysis.

A new catechol-substituted monostyryl boradiazaindacene (BODIPY)-based lanthanide-free colorimetric and fluorogenic probe was developed for the sequential detection of Cu 2+ ions and dipicolinic acid (DPA), a distinctive biomarker of bacterial endospores, with high sensitivity and selectivity. In the presence of Cu 2+ ions, the blue solution of the probe changes to cyan and the fluorescence is quenched, however, the cyan color changes to blue immediately and the fluorescence is restored on contact with DPA, resulting from competitive binding of DPA that interact with Cu 2+ ions. A practical application by using Geobacillus stearothermophilus spores was further studied and as low as 1.0 x 10 5 spores were detected., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The germination of Clostridium difficile spores is an important stage of the C. difficile life cycle. In other endospore-forming bacteria, the composition of the medium in which the spores are generated influences the abundance of germination-specific proteins, thereby influencing the sensitivity of the spores towards germinants. In C. difficile media composition on the spores has only been reported to influence the number of spores produced. One of the measures of spore germination is the analysis of the release of DPA from the spore core. To detect DPA release in real time, terbium chloride is often added to the germination conditions because Tb 3+ complexes with the released DPA and this can be detected using fluorescence measurements. Although C. difficile spores germinate in response to TA and glycine, recently calcium was identified as an enhancer for spore germination. Here, we find that germination by spores prepared in peptone rich media, such as 70:30, is positively influenced by terbium. We hypothesize that, in these assays, Tb 3+ functions similarly to calcium. Although the mechanism(s) causing increased sensitivity of the C. difficile spores that are prepared in peptone rich media to terbium is still unknown, we suggest that the TbCl 3 concentration used in the analysis of C. difficile DPA release be carefully titrated so as not to misinterpret future findings., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Since anthrax spores are highly lethal to human beings and animals, and also potential biological warfare agents, it is highly desirable to develop simple, robust and easy-device sensors that are rapid and sensitive, and can selectively detect the Bacillus anthrax biomarker dipicolinic acid (DPA) quantitatively. Herein, we report a ratiometric luminescent "turn-on" sensor via mixing Eu 3+ ions, sodium polyacrylate and internal luminescence reference in water, which can identify the Bacillus anthrax biomarker dipicolinic acid (DPA) quantitatively with outstanding selectivity over aromatic ligands and amino acids, even including all of the 5 DPA isomers.

Based on a BODIPY molecular rotor and a zinc-dipicolylamine receptor, we designed a fluorogenic probe for the detection of apoptosis. Being poorly emissive in solution and with healthy cells, it selectively binds phosphatidylserine of early apoptotic cells and internalizes into late apoptotic cells, lighting up its green fluorescence.

Bacillus spp. are spore-forming bacteria, and some of them, including Bacillus cereus and Bacillus anthracis, are pathogens. Dipicolinic acid (DPA) has been recognized as a biomarker for spore-forming bacteria. Thus, developing rapid sensing methods to spot the presence of DPA in suspicious samples is significant. In this study, we employ complexes of glutathione-capped gold nanoclusters (Au@GSH NCs) with Cu2+ as sensing probes against DPA. Au@GSH NCs possess orange-reddish fluorescence. However, their fluorescence is significantly quenched in the presence of Cu2+. In the presence of DPA, the fluorescence of Au@GSH NCs can be restored because DPA can easily remove Cu2+ on the NCs through chelation based on the high formation constant (log K = 7.97) between Cu2+ and DPA. Therefore, on the basis of this fact, Au@GSH NC-Cu2+ complexes are used as turn-on fluorescence probes against DPA. Unlike most of the existing sensing methods, the developed Au@GSH-Cu2+-based sensing method is not affected by the presence of phosphates, which can be commonly found in real samples. The limit of detection of using the developed sensing method toward DPA can reach as low as ∼19 nM. In addition, we also demonstrate the feasibility of using the developed sensing method for detection and quantification of DPA in soil samples and B. cereus spore lysates.

The sensitive, selective and point-of-care detection of dipicolinic acid (DPA) is of great significance for the prevention of the anthrax virus and the containment of bioterrorism. In this work, a multi-color fluorescent nanoprobe composed of lanthanides and magnetic nanoparticles (Fe 3 O 4 @CePO 4 :Tb-EDTA-Eu) has been designed, in which the portion of Fe 3 O 4 @CePO 4 :Tb can be used as the internal stable signal of green fluorescence, while the EDTA-Eu part can be used as the sensitive reaction signal for monitoring DPA. Upon the addition of DPA, the red fluorescence of Eu 3+ ions is significantly enhanced, while the fluorescent color of the nanoprobes can change from green to red (such as yellow-green, orange-yellow and orange-red), achieving visual multi-color fluorescent detection even by the naked eye. By using the magnetic separation method, the composites can be easily purified for point-of-care testing. More importantly, the nanoprobe fixed test pieces enable real-time analysis of DPA by using an easy-to-access color-scanning application on a smartphone. Furthermore, the fluorescence intensity can be quenched by the addition of Cu 2+ , which leads to a rewritable nanosensor and can be used in the detection of cysteine (Cys) with high sensitivity. With the addition of Cys, this erasable nano detection platform can also display the original multi-color visual point-of-care detection. With further optimization, this new type of multi-color fluorescent assay is promising in point-of-care clinics for multi-target diagnostics.

The evolution during ripening of Beta vulgaris (var. Pablo) on colour and betalain composition, not previously conducted in conjunction in red beets, has been examined. According to the results, it could be asserted that the ripening stage significantly (p < 0.05) influenced on all the studied parameters. On the basis of the betalain content, the optimum ripening stage corresponded to a medium weigh-to-calibre ratio, in the light of the significantly (p < 0.05) higher content of betalains, especially betanin and vulgaxanthin I. Moreover, colour attributes also differed during ripening, having the medium-ripened beetroots a significantly (p < 0.05) more reddish hue (h ab ) and lower lightness (L*), probably due to the higher content of betaxanthins in this stage. The colour differences among red beets in the stage II and the rest of stages were visually appreciable (ΔE* ab  > 3) and mainly qualitative. A new range of opportunities for diversification of colorant market, from a nutritional and colorimetric point of view, could be possible by employing red beets with different stages of ripening.

Hydroxyapatite nanoparticles (HAP-NPs) were rendered fluorescence by doping with Eu(III) ion. The resulting fluorescent NPs are shown to be viable probes for sensitive and selective determination of dipicolinic acid (DPA), a major constituent of bacterial spores as used in bioterrorism. It is found that the addition of DPA to solutions of such HAP-NPs result in an enhancement of fluorescence due to the coordination of DPA with the Eu(III) dopant. The assay allows DPA to be detected in the 0.1 to 40 μM concentration range and with a 77 nM detection limit. The assay was applied to the detection of spores of Bacillus subtilis. The attractive properties of the probe make it a promising candidate for used in rapid detection of pathogenic bacterial spores. Graphical abstract Fluorescent hydroxyapatite nanoparticles (HAP-NPs) are shown to be a viable probe for detection of dipicolinic acid, a major constituent of bacterial spores. The red asterisks represent the fluorescence intensity of the HAP-NPs.

Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb 3+ and Eu 3+ , and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

We have designed and synthesized a novel, water-soluble naphthalimide-histidine receptor (1) with excellent fluorescent properties. Functioning of the synthesized receptor was performed through developing their DNA-receptor hybrid assembly (DRHA), which has shown significant changes in the emission profile upon interactions with dipicolinic acid (DPA), a biomarker for Bacillus anthracis spores. DRHA showed fluorescence enhancement upon binding with DPA with the characteristic of internal charge transfer. It is notable that this assembly exhibited a significant limit of detection (12 nM) toward DPA. The mechanism of sensing was fully defined using ethidium bromide (EtBr) interaction studies as well as Fourier transform infrared spectroscopic analysis, which describes the binding mode of DRHA with DPA. This assembly selectively interacts with DPA over other anions, common cellular cations, and aromatic acids in aqueous media.

Bioprospection of marine invertebrates has been predominantly biased by the biological richness of tropical regions, thus neglecting macro-organisms from temperate ecosystems. Species that were not the object of studies on their biochemical composition include the Heterobranchia gastropods Armina maculata , Armina tigrina and Aglaja tricolorata , inhabitants of the Portuguese Atlantic coastal waters. Here, we present for the first time the fatty acid profile of neutral lipids and homarine content of these three species. Qualitative and quantitative differences in the fatty acid content among species points to the existence of a fatty acid profile of neutral lipids, particularly of each genus. The results from cytotoxicity assays, using the acetonic extracts of the gastropods on human gastric adenocarcinoma (AGS) and human lung adenocarcinoma (A549) cell lines, revealed a pronounced cytotoxic effect of the A. tigrina extract on both cell lines (IC 50 values of 68.75 and 69.77 μg mL −1 for AGS and A549, respectively). It is worth noting the significant reduction of NO levels in LPS-challenged RAW 264.7 macrophages exposed to A. tricolorata extract, at concentrations as low as 125 μg mL −1 .

A novel ratiometric colorimetric and fluorescent dual probe based on Eriochrome Black T (EBT)-Eu 3+ 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 3+ ions formed a 1:1 coordination pair in water. In the presence of Eu 3+ 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 3+ complex was observed. In addition, the sensitivity of the system was further evaluated on Geobacillus stearothermophilus spores and as low as 2.5 × 10 5 spores were detected.

Europium(III)-doped carbon dots (Eu-CDs) were prepared from citric acid and europium nitrate via a one-pot pyrolytic method. The Eu-CDs emit intense blue fluorescence (with excitation/emission peaks at 365/465 nm), are water soluble and biocompatible. On addition of 2,6-dipicolinic acid (DPA; an anthrax biomarker), ligand-to-ion energy transfer occurs from DPA to Eu(III) which has a red emission peaking at 615 nm. This results in an increase of the intensity of the red fluorescence. DPA can be detected by the ratio of fluorescence intensities at 616 and 475 nm. The method has an analytical range that extends from 5 to 700 nmol·L -1 , with a 5 nmol·L -1 detection limit. The Eu-CDs also were incorporated into a test paper for visual detection of DPA with a portable UV lamp and a smartphone. In this case, the detection limit is 1 μmol·L -1 . The Eu-CDs internalize well into HeLa cells, and this paves the way to bioimaging. Graphical abstract Schematic of a method for visual detection of 2,6-dipicolinic acid (DPA, an anthrax biomarker) by using a test stripe impregnated with europium(III)-doped carbon dots (Eu-CDs).

Dipicolinic acid (DPA) can cause neurotoxicity and is abundant in bacterial spores. Although analytical methods have been reported for DPA detection with high sensitivity, their selectivity toward DPA is declined greatly in the presence of phosphates in the samples. In this study, we developed an approach for DPA detection that is not affected by the presence of phosphates. A colorimetric method based on the use of gold nanoparticles (AuNP) complexed with Ca 2+ as sensing agents was explored for DPA detection. Calcium ions and glutathione-capped gold nanoparticles (AuNPs@GSH) can easily form complexes (Ca 2+ -AuNP@GSH) through GSH-Ca 2+ chelation, leading to the aggregation of AuNPs@GSH. The aggregation resulting from the complexes of AuNPs@GSH and Ca 2+ can be reversed with the addition of DPA owing to the high formation constant (log K f  = 4.4) between DPA and Ca 2+ . Furthermore, the color of AuNPs@GSH changes from red to purple when complexed with Ca 2+ , returning to red upon addition of DPA. The limit of detection of this sensing method toward DPA was estimated to be as low as ~ 2 μM. The feasibility of using the sensing method for quantitative detection of DPA in soil and Bacillus cereus spore samples was also demonstrated. Graphical abstract A AuNP-based colorimetric sensing method against dipicolinic acid is developed.

A novel chitosan-based ratiometric fluorescent probe incorporating an EDTA-Eu 3+ complex as the sensing unit and fluorescein dye as the internal standard was designed to detect dipicolinic acid (DPA) as an anthrax biomarker with high sensitivity and selectivity. The fluorescence intensity of fluorescein dye attached to the chitosan backbone remains constant as an internal reference, while the Eu 3+ emission increased linearly upon the consecutive addition of DPA. The selectivity studies were performed by adding different competitive aromatic ligands to the sensing environment and no signifacant fluorescence response was observed. The results demonstrated the superior selectivity of the system to DPA. Overall, this novel chitosan-based ratiometric fluorescent probe enables ratiometric and sensitive DPA detection over nanomolar concentrations (as low as 10nM) and displays straightforward selectivity over other competitive aromatic ligands., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Chromium picolinate is one of the important Cr 3+ resources and is widely used in animal production. A convenient, reliable and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative determination of chromium picolinate in animal feeds. Feed samples were extracted with acetonitrile and subsequently cleaned up by solid phase extraction cartridges Supelclean™ LC-18. Chromium picolinate was efficiently separated with a Waters ACQUITY UPLC ® BEH C18 column, ionized with electrospray ion source in positive mode (ESI + ), and quantitatively determined by tandem mass spectrometry in multiple reaction monitoring mode. Standard calibration curve of chromium picolinate in the concentration range from 0.5 to 1000ng/mL was obtained with good linearity correlation coefficient (R 2 =0.9982). Average recoveries ranged from 95.37%∼105.54%, as detected by spiking 0.02∼640mg/kg of chromium picolinate in complete feed, concentrated feed and premix. Intra-day and inter-day coefficient of variation were 0.59%∼6.67% and 2.36%∼6.97%, respectively. The limits of quantitation were 0.02mg/kg, 0.025mg/kg, and 2mg/kg for complete feed, concentrated feed, and premix, respectively. Actual sample analysis indicated that the developed method can be an effective tool to monitoring CrPic content in animal feed., (Copyright © 2017. Published by Elsevier B.V.)

An easy and effective strategy for synthesizing a ratiometric fluorescent nanosensor has been demonstrated in this work. Novel fluorescent BSA-AuNPs@Tb-AMP (BSA, bovine serum albumin; AMP, adenosine 5'-monophosphate; AuNPs, Au nanoparticles) metal-organic framework (MOF) nanostructures were synthesized by encapsulating BSA-AuNPs into Tb-AMP MOFs for the detection of 2,6-pyridinedicarboxylic acid (DPA) and Hg 2+ . DPA could strongly co-ordinate with Tb 3+ to replace water molecules from the Tb 3+ center and accordingly enhanced the fluorescence of Tb-AMP MOFs. The fluorescence of BSA-AuNPs at 405 nm remained constant. While the fluorescence of BSA-AuNPs at 635 nm was quenched after Hg 2+ was added, the fluorescence of Tb-AMP MOFs remained constant. Accordingly, a ratiometric fluorescence nanosensor was constructed for detection of DPA and Hg 2+ . The ratiometric nanosensor exhibited good selectivity to DPA over other substances. The F 545 /F 405 linearly increased with increase of DPA concentration in the range of 50 nM to 10 μM with a detection limit as low as 17.4 nM. F 635 /F 405 increased linearly with increase of Hg 2+ concentration ranging from 50 nM to 1 μM with a detection limit as low as 20.9 nM. Additionally, the nanosensor could be successfully applied for the determination of DPA and Hg 2+ in running water., (Copyright © 2017 John Wiley & Sons, Ltd.)

Field, reliable, and ultrasensitive detection of dipicolinic acid (DPA), a general biomarker of bacterial spores and especially Bacillus anthracis, is highly desirable but still challenging in current biometric security emergency response system. Herein we report an environmentally safe mercury(II) ions-mediated and competitive coordination interaction based approach for rationally designed surface-enhanced Raman scattering (SERS)-active gold nanoparticles (AuNPs), enabling rapid, ultrasensitive and zero-background detection of DPA without the pretreatment of samples. By means of competitiveness, these papain-capped gold nanoparticles (P-AuNPs) are induced to undergo controllable aggregation upon the addition of Hg 2+ ions and DPA with a concentration range (1 nM∼8 μM), which correspondingly cause quantitative changes of SERS intensity of cresyl violet acetate (CVa) conjugated AuNPs. The decreased Raman intensity obtained by subtracting two cases of additives that contain only Hg 2+ and the mixture of Hg 2+ and DPA is proportional to the concentration of DPA over a range of 1 nM∼8 μM (R 2 = 0.9824), with by far the lowest limit of detection (LOD) of 67.25 pM (0.01 ppb, S/N = 3:1). Of particular significance, mercury(II) ions actually play two roles in the process of measurements: a mediator for two designed competitive ligands (DPA and papain), and also a scavenger for the possibly blended ligands due to the different interaction time between DPA and the interferent with Hg 2+ ions, which guarantees the interference-free detection of DPA even under real conditions.

Gold nanoparticles (GNPs) functionalized with ethylenediamine-lanthanide complexes (Eu-GNPs and Tb-GNPs) were used for the selective fluorescent detection of dipicolinic acid (DPA), a unique biomarker of bacterial spores, in water. Particles were characterized by transmission electron microscopy and zeta potential measurements. The coordination of DPA to the lanthanides resulted in the enhancement of the fluorescence. A selective response to DPA was observed over the nonselective binding of aromatic ligands. The ligand displacement strategy were also employed for the ratiometric fluorescent detection of DPA. 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedion (TFNB) was chosen as an antenna to synthesize ternary complexes. The addition of DPA on EuGNP:TFNB ternary complex quenched the initial emission of the complex at 615nm and increased the TFNB emission at 450nm when excited at 350nm. The results demonstrated that the ratiometric fluorescent detection of DPA was achieved by ligand displacement strategy., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Airborne bacteria are components of the atmospheric aerosol particles and can be responsible of allergic disease, regardless of their viability. In this paper, we report a method for the determination of total (viable and nonviable) bacterial content in airborne particles, using muramic and dipicolinic acids as biomarkers of bacteria and bacterial spores, respectively. The analytical procedure was optimized with bacteria and spores of Bacillus subtilis. After extraction and purification, the two biomarkers were analyzed by HPLC-ESI-MS/MS and their percentage was evaluated to be used as conversion factor. The present method for the determination of the total bacterial content was then applied to environmental samples, after a proper collection in an urban site. Thanks to the use of a low pressure impactor, capable of fractionating particles into the range of 0.03-10 μm, it was also possible to study the bacterial content in ultrafine, fine, and coarse particulate matter. The results from this study showed that muramic and dipicolinic acids can be determined together in one chromatographic run in reversed phase ion pair chromatography. Bacteria were more abundant than bacterial spores in the urban atmosphere, both showing a higher concentration in the coarse fraction of particles, although bacteria and bacterial spore amounts per unit mass of ultrafine particles were higher than in fine and coarse particles.

The sensitive detection of dipicolinic acid (DPA) is strongly associated with the sensing of bacterial organisms in food and many types of environmental samples. To date, the demand for a sensitive detection method for bacterial toxicity has increased remarkably. Herein, we investigated the DPA detection potential of a water-dispersible terbium-metal organic framework (Tb-MOF) based on the fluorescence quenching mechanism. The Tb-MOF showed a highly sensitive ability to detect DPA at a limit of detection of 0.04nM (linear range of detection: 1nM to 5µM) and also offered enhanced selectivity from other commonly associated organic molecules. The present study provides a basis for the application of Tb-MOF for direct, convenient, highly sensitive, and specific detection of DPA in the actual samples., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A ratiometric fluorescent sensor based on luminescent bio-metal-organic framework was prepared by exchanging both Tb(3+) and Eu(3+) cations into anionic bio-MOF-1. Due to a highly efficient energy transfer from Tb(3+) to Eu(3+) (>89%), emission color of Tb/Eu@bio-MOF-1 was orange-red even though Tb(3+) was the dominant content in this Tb/Eu co-doping material. More interestingly, this energy transfer process could be modulated by dipicolinic acid (DPA), an unique biomarker for bacillus spores. With DPA addition, corresponding DPA-to-Tb(3+) energy transfer was gradually enhanced while the energy transfer from Tb(3+) to Eu(3+) was significantly weakened. By regulating the energy transfer process in Tb/Eu@bio-MOF-1, visual colorimetric sensing of DPA in porous MOF was realized for the first time. Detection limit of Tb/Eu@bio-MOF-1 for DPA was 34nM, which was much lower than an infectious dosage of Bacillus anthracis spores (60μM) for human being. Besides, Tb/Eu@bio-MOF-1 showed a remarkable selectivity over other aromatic ligands and amino acids. More importantly, this porous ratiometric sensor worked equally well in human serum. These particularly attractive features of Tb/Eu@bio-MOF-1 made the direct, rapid and naked-eye detection of DPA for practical application possible., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Surface-enhanced Raman measurements of <1 μL analyte/colloid meso-droplets on superhydrophobic wires with hydrophilic tips allowed dipicolinic acid, a spore biomarker for Bacillus anthracis (anthrax), to be detected at 10(-6) mol dm(-3). This is equivalent to 18 spores, significantly below the infective dose of 10(4) spores and 2 orders of magnitude better than previous measurements.

Objectives: Elevated levels of pipecolic acid (PA), α-aminoadipic semialdehyde (AASA) and its cyclic form Δ1-piperideine-6-carboxylate (P6C) are characteristic of pyridoxine dependent epilepsy (PDE), a rare disorder of inborn error of metabolism. Recent studies showed the effectiveness of dietary therapy in PDE patients and emphasized the importance of the assessment of these metabolites for monitoring treatment efficacy. The objective of this study was to develop a robust and sensitive method for simultaneous quantification of AASA-P6C and PA in plasma and urine., Design and Methods: Plasma and urine samples were derivatized with 3N HCl in n-butanol (v/v) and injected onto ACQUITY BEH-C18 column. A gradient of water/methanol containing 0.1% formic acid was used for the chromatographic separation of AASA, P6C and PA. The analytes' concentrations were calculated using their calibration curves and the sum of AASA and P6C (AASA-P6C) was calculated. To evaluate the clinical utility of this test, samples from unaffected controls and patients with confirmed PDE were analyzed., Results: The performance characteristics of the assay as well as sample stability and interferences were determined. The intra- and inter- assay CVs were ≤2.9% and ≤10.9% for AASA-P6C, and ≤3.3% and ≤12.6% for PA, respectively. Reference ranges for AASA-P6C and PA in plasma and urine were established. Comparison of values obtained from unaffected controls and PDE patients showed high clinical sensitivity and specificity of the assay., Conclusions: This novel method for the simultaneous quantification of AASA-P6C and PA in plasma and urine can be used in a clinical laboratory setting for the diagnosis and monitoring of patients with PDE., (Copyright © 2016 Elsevier B.V. All rights reserved.)

We herein reported a method for the simultaneous detection of trace Cr(VI), Cr(III), and chromium(III) picolinate (CrPic) in foods using CE-ICP-MS together with ultrasonic-assisted extraction. The Cr(III) (Cr(3+) ) was chelated with trans-1,2-diaminocyclohexane-N,N,N´,N´-tetraacetic acid (DCTA) to form a single charged Cr-DCTA(-) complex. Then, Cr(VI) (CrO4 (2-) ), Cr-DCTA(-) , and CrPic were separated by CE within 8 min under a separation voltage of -13 KV followed by their monitoring with ICP mass spectrometer (ICP-MS). The proposed method is simple, effective, and sensitive. It has an instrument detection limit of 0.10, 0.18, and 0.20 ngCr/mL for Cr(VI), Cr(III), and CrPic, respectively. With the help of the methods, we have successfully determined Cr(VI), Cr(III), and CrPic in nutritional supplement (CrPic yeast tablet) with an RSD (n = 5) <6% and a recovery of 93-103%. The experimental results showed that CrPic was the main speciation of chromium in the nutritional supplement, with a concentration of 1514.6 μg Cr/g., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A ratiometric fluorescent nanoprobe based on terbium functionalized carbon dots (CDs) was designed to detect dipicolinic acid (DPA) as an anthrax biomarker with high selectivity and sensitivity. CDs were generated by one-step synthesis using an ethylenediaminetetraacetic acid precursor, and served as a scaffold for coordination with Tb(3+) and a fluorescence reference.