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Biothiols, such as cysteine (Cys), glutathione (GSH), and homocysteine (Hcy), play crucial roles in various physiological processes and serve as biomarkers for oxidative stress and redox homeostasis. Their structural similarities, however, pose significant challenges in selective detection and quantification, limiting the availability of suitable probes. Here, we report the design and synthesis of a novel ratiometric fluorescent sensor based on a seleno-BODIPY (Se-BODIPY) derivative, enabling rapid discrimination and quantification of Cys, Hcy, and GSH with low detection limits (Cys = 0.8 μM, Hcy = 20.4 μM, and GSH = 35.9 μM) via fluorescence. The probe exhibits high selectivity towards these biothiols over 11 amino acids, operating through dual-mode detection (absorption and emission spectra) with a visible color change from blue to orange (Cys/Hcy) or pink (GSH) in a turn-on fluorescence process. Notably, the distinct reaction mechanisms between Se-BODIPY and GSH versus Cys/Hcy lead to a more prominent blue shift for Cys/Hcy, facilitating their differentiation. Kinetic studies further differentiate Cys from Hcy, with the BODIPY reacting much faster with Cys than the latter. The effectiveness of the sensor was demonstrated in quantifying biothiols in urine samples, providing a non-invasive method with high recovery rates. Additionally, its incorporation into paper strips allows detection of biothiols in water samples via visible and UV light-induced color changes, indicating its potential for solid-state detection without organic solvents.

There is an urgent need to develop sensitive, non-invasive biomarkers that can track airway inflammatory activity for patients with cystic fibrosis (CF). Urinary glutathione sulfonamide (GSA) levels correlate well with GSA levels in BAL samples and other markers of neutrophilic inflammation, suggesting that this biomarker may be suitable for tracking disease activity in this population. We recruited 102 children (median 11.5 years-old) and 64 adults (median 32.5 years-old) who were admitted to hospital for management of an acute pulmonary exacerbation and/or eradication of infectious agents such as Pseudomonas aeruginosa or Staphylococcus aureus. Our aim was to explore how urinary GSA levels changed across admission timepoints. Urine samples were collected at admission and discharge, and GSA measured by liquid chromatography with mass spectrometry. Paired admission-discharge results were compared using Wilcoxon signed-rank test. Paired admission-discharge samples were available for 53 children and 60 adults. A statistically significant difference was observed between admission-discharge for children and adults. Spearman's correlation analysis identified a correlation between urinary GSA levels and sex and S. aureus infection for children only. Our preliminary findings suggest that urinary GSA is responsive to the resolution of an acute pulmonary exacerbation and therefore warrants further studies in this population., Competing Interests: Declaration of competing interest T.L. Blake holds a Children's Hospital Foundation ECR Fellowship for salary support and an Australian CFA Research Trust Innovation Grant for unrelated research. P.D. Sly holds NHMRC Investigator and Clinical Trials & Cohort Study grants. Authors C.E. Wainwright and S.C. Bell have received institutional payments for chairing and speaking at educational events (Vertex Pharmaceuticals). C.E. Wainwright also declares participating in steering committee and advisory board sessions for Vertex Pharmaceuticals. N. Dickerhof holds a Sir Charles Hercus Research Fellowship from the Health Research Council of New Zealand. Remaining authors I. Andersen, D.W. Reid B.R. Smith and A.J. Kettle declare that they have no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Humans are chronically exposed to furan, a potent liver toxicant and carcinogen that occurs in a variety of heat-processed foods. Assessment of human exposure based on the furan content in foods is, however, subject to some uncertainty due to the high volatility of furan. Biomarker monitoring is thus considered an alternative or complementary approach to furan exposure assessment. Previous work suggested that urinary furan metabolites derived from the reaction of cis-2-butene-1,4-dial (BDA), the reactive intermediate of furan, with glutathione (GSH) or amino acids may serve as potential biomarkers of furan exposure. However, some metabolites were also reported to occur in urine of untreated animals, indicating either background contamination via animal feed or endogenous sources, which may limit their suitability as biomarkers of exposure. The overall aim of the present study was to accurately establish the correlation between external dose and concentration of furan metabolites in urine over time and to discriminate against endogenous formation and furan intake via feed. To this end, the furan metabolites GSH-BDA (N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-L-cysteinylglycine), NAcLys-BDA (R-2-(acetylamino)-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid), NAcCys-BDA-NAcLys (N-acetyl-S-[1-[5-(acetylamino)-5-carboxypentyl]-1H-pyrrol-3-yl]-L-cysteine) and NAcCys-BDA-NAcLys sulfoxide (N-acetyl-S-[1-[5-(acetylamino)-5-carboxypentyl]-1H-pyrrol-3-yl]-L-cysteine sulfoxide) were simultaneously analyzed by stable isotope dilution ESI-LC-MS/MS as unlabeled and [ 13 C 4 ]-furan dependent metabolites following oral administration of a single oral dose of isotopically labelled [ 13 C 4 ]-furan (0.1, 1, 10, 100 and 1000 µg/kg bw) to male and female F344/DuCrl rats. Although a linear correlation between urinary excretion of [ 13 C 4 ]-furan-dependent metabolites was observed, analysis of unlabeled NAcLys-BDA, NAcCys-BDA-NAcLys and NAcCys-BDA-NAcLys sulfoxide revealed substantial, fairly constant urinary background levels throughout the course of the study. Analysis of furan in animal feed excluded feed as a source for these background levels. GSH-BDA was identified as the only furan metabolite without background occurrence, suggesting that it may present a specific biomarker to monitor external furan exposure. Studies in humans are now needed to establish if analysis of urinary GSH-BDA may provide reliable exposure estimates., (© 2024. The Author(s).)

A dual-emission ratio-fluorescent sensing nanohybrid based on Radix Hedysari green-synthesized carbon quantum dots (CDs) and glutathione-functionalized gold nanoclusters (GSH-AuNCs) had been developed for the determination of cefodizime sodium (CDZM). The designed fluorescence nanohybrid had two significant fluorescence emission peaks at 458 nm and 569 nm when excited at 360 nm, which was attributed to the CDs and GSH-AuNCs. With the addition of CDZM, the fluorescence at 458 nm was slightly weakened while the fluorescence at 569 nm was enhanced obviously. Based on the relationship between the I 569 /I 458 fluorescence intensity ratio and the concentration of CDZM, the designed nanohybrid exhibited a good linearity range of 1.0-1000.0 μM and the limit of detection (LOD) was 0.19 μM. The method was finally applied in the detection of CDZM in urine, showing the potential applications in complicated biological samples.