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The luminescent film materials sensitive to external stimuli are important to develop new types of optical sensors and switches. Herein we report organic–inorganic hybrid ultrathin films (UTFs) with reversible luminescence response to nitroaromatic explosive compounds by the use of layer-by-layer assembly of optical brightener BBU and Mg–Al-layered double hydroxide (LDH) nanosheets. UV-Visible absorption and fluorescence spectroscopy showed an orderly growth of the BBU/LDH films upon increasing the number of deposition cycle. XRD, AFM and SEM measurements indicated that the films feature periodic layered structure with a period of ca. 2 nm as well as uniform surface morphology. The BBU/LDH UTFs exhibit well-defined one/two-photon polarized photoemission with the anisotropy as high as 0.38. Moreover, the UTFs show a fast, selective and reversible luminescence response to different nitroaromatic explosives with the most significant luminescent red-shift occurring for picric acid; in addition, by combining suitable luminescent building blocks, the films can also be extended to other dual-color luminescence systems, which exhibit changes in both luminescence intensity and ratiometric fluorescence upon interaction with explosives, enlightening that these films can serve as new types of selective solid luminescent sensors towards nitroaromatic compounds. [ABSTRACT FROM AUTHOR]

The synthesis of gram quantities of the TF antigen (β-ᴅ-Gal-(1→3)-α-ᴅ-GalNAc) and its 3'-sulfated analogue with a TEG-N 3 spacer attached is described. The synthesis of the TF antigen comprises seven steps, from a known N -Troc-protected galactosamine donor, with an overall yield of 31%. Both the spacer (85%) and the galactose moiety (79%) were introduced using thioglycoside donors in NIS/AgOTf-promoted glycosylation reactions. The 3'-sulfate was finally introduced through tin activation in benzene/DMF followed by treatment with a sulfur trioxide-trimethylamine complex in a 66% yield., (Copyright © 2024, Reihill et al.)

Background: Ascorbic acid (AA), dopamine (DA), uric acid (UA), and nitrite (NO2-) are essential biomarkers for human metabolism and can be used to indicate some chronic diseases and metabolic disorders, including scurvy, Parkinson's disease, hyperuricemia, and kidney disease., Objective: A multifunctional electrochemical sensor that can integrate the detection of these species was constructed using nanoporous gold (NPG) as a recognition element to modify glassy carbon electrode (GCE)., Methods: The electrochemical performance of the multifunctional electrochemical sensor was investigated toward AA, DA, UA, and NO2- in citrate buffer solution (CBS, 100 mM, pH 4.0) and human serum using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods., Results: In the quaternary mixture detection, the resulting NPG/GCE electrode displayed four independent oxidation peaks with wide peak separations. Further, the NPG/GCE electrode showed good linear responses with the sensitivities of 32, 1103, 71, and 147 μA/mM/cm2 and the detection limits of 1.58, 0.17, 0.37, and 0.36 μM for AA, DA UA, and NO2-, respectively. Additionally, the NPG/GCE electrode exhibited great anti-interference and was successfully applied in human serum samples., Conclusions: These results indicate that the NPG/GCE electrode can simultaneously and selectively detect AA, DA, UA, and NO2-, which has the potential for application and diagnosis in the screening and diagnosis of chronic diseases and metabolic disorders., Highlights: A multianalyte electrochemical sensor was fabricated for human metabolites detection. The sensor displayed good performance in the simultaneous detection of AA, DA, UA, and NO2- and applied to human serum samples., (© AOAC INTERNATIONAL 2020. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The β4-N-acetylgalactosaminyltransferase 3 (B4GALNT3) transfers GalNAc in a β1,4-linkage to GlcNAc forming the LacdiNAc (LDN) determinant on oligosaccharides. The LacdiNAc-binding adhesin (LabA) has been suggested to mediate attachment of Helicobacter pylori to the gastric mucosa via binding to the LDN determinant. The O-glycan core chain specificity of B4GALNT3 is poorly defined. We investigated the specificity of B4GALNT3 on GlcNAc residues carried by O-glycan core 2, core 3 and extended core 1 precursors using transient transfection of CHO-K1 cells and a mucin-type immunoglobulin fusion protein as reporter protein. Binding of the LabA-positive H. pylori J99 and 26695 strains to mucin fusion proteins carrying the LDN determinant on different O-glycan core chains and human gastric mucins with and without LDN was assessed in a microtiter well-based binding assay, while the binding of 125 I-LDN-BSA to various clinical H. pylori isolates was assessed in solution. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and western blotting confirmed the requirement of a terminal GlcNAc for B4GALNT3 activity. B4GALNT3 added a β1,4-linked GalNAc to GlcNAc irrespective of whether the latter was carried by a core 2, core 3 or extended core 1 chain. No LDN-mediated adhesion of H. pylori strains 26 695 and J99 to LDN determinants on gastric mucins or a mucin-type fusion protein carrying core 2, 3 and extended core 1 O-glycans were detected in a microtiter well-based adhesion assay and no binding of a 125 I-labelled LDN-BSA neoglycoconjugate to clinical H. pylori isolates was identified.