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Membrane emulsification can obtain microspheres with relatively uniform particle size and pore size, which has unique advantages in the synthesis of polymer microsphere adsorbents and the enrichment and separation of organic compounds. In this study, the Hydrophilic Lipophilic Balance (HLB) solid phase extraction microspheres were prepared by membrane emulsification technique and was used in the pretreatment of samples to detect 25-hydroxy vitamin D2 (25OH-VD2) and 25-hydroxy vitamin D3 (25OH-VD3) in serum by UPLC-MS/MS for the first time. To confirm the efficacy of membrane-emulsified (ME) HLB microspheres, three types of microspheres, including ME HLB microspheres, non-membrane-emulsified (non-ME) HLB microspheres and commercial HLB microspheres, were compared for the pretreatment of 25OH-VD2 and 25OH-VD3. The performance of HLB microspheres was characterized based on the sample recovery values acquired by UPLC-MS/MS analysis. Results showed that among the three types of microspheres, ME HLB microspheres showed the best performance and demonstrated good adsorption properties for 25OH-VD2 and 25OH-VD3. The recoveries range of 25OH-VD2 and 25OH-VD3 were 96.7–101.4 and 98.7–104.9%, respectively, and the coefficients of variation were 0.67–1.24 and 1.39–2.28%, respectively, which were superior to those of commercial HLB microspheres and non-ME HLB microspheres. Additionally, due to their excellent homogeneity, the ME HLB microspheres exhibited good precision in the determination of low values of 25OH-VD2 and 25OH-VD3, indicating accurate and simple detection of 25OH-VD2 and 25OH-VD3 with a broad potential for further development. [ABSTRACT FROM AUTHOR]

AbstractTime-resolved fluorescent nanospheres (TRFNs) are polymer nanospheres with special functional groups on the surface loaded with rare earth complexes which emit fluorescence when irradiated by ultraviolet light. TRFNs offer spherical morphology, homogeneity, good dispersity, large specific surface area, easy chemical modification, high loading capacity and good biocompatibility. The rare earth complexes possess unique properties that render them highly sensitive and capable of effectively excluding unspecific fluorescence. Hence, they constitute an excellent labeling material for the time-resolved fluorescence immunochromatographic assay (TRFIA). The developed method has a linear response to ferritin from 6 to 1000 ng/mL with a detection limit of 3.5 ng/mL, good reproducibility, and good accuracy compared with commercial chemiluminescence measurements of serum. These results suggest that the reported TRFN has utility for time-resolved fluorescence immunochromatographic assays. [ABSTRACT FROM AUTHOR]

Tetrathiatriarylmethyl (TAM, trityl) radicals have found wide applications as spin probes/labels for EPR spectroscopy and imaging, and as polarizing agents for dynamic nuclear polarization. The high hydrophilicity of TAM radicals is essential for their biomedical applications. However, the synthesis of hydrophilic TAM radicals (e.g. OX063) is extremely challenging and has only been reported in the patent literature, to date. Herein, an efficient synthesis of a highly water‐soluble TAM radical bis(8‐carboxyl‐2,2,6,6‐tetramethylbenzo[1,2‐d:4,5‐d′]bis([1,3]dithiol‐4‐yl)‐mono‐(8‐carboxyl‐2,2,6,6‐tetrakis(2‐hydroxyethyl)benzo[1,2‐d:4,5‐d′]bis([1,3]dithiol‐4‐yl)methyl (TFO), which contains four additional hydroxylethyl groups, relative to the Finland trityl radical CT‐03, is reported. Similar to OX063, TFO exhibits excellent properties, including high water solubility in phosphate buffer, low log P, low pKa, long relaxation times, and negligible binding with bovine serum albumin. On the other hand, TFO has a sharper EPR line and higher O2 sensitivity than those of OX063. Therefore, in combination with its facile synthesis, TFO should find wide applications in magnetic resonance related fields and this synthetic approach would shed new light on the synthesis of other hydrophilic TAM radicals. [ABSTRACT FROM AUTHOR]

Introduction: We compared the clinical characteristics of vaccinated and non-vaccinated Omicron patients in order to provide a reference for the clinical diagnosis and treatment of coronavirus disease 2019 (COVID-19)., Methodology: This study included 360 patients diagnosed with COVID-19. The serum immunoglobulin G (IgG) and serum immunoglobulin M (IgM) antibody levels of the patients and the duration of virus shedding were analyzed according to age, gender, vaccine dose, and the time from the most recent vaccination to the onset of Omicron infection., Results: Age (OR = 0.974), days from last vaccination to onset ≤ 180 days (OR = 4.409), and booster dose of the vaccine (OR = 4.999) were protective factors associated with patients who were IgG antibody positive. The duration of virus shedding in IgG -antibody-positive patients was 9 (8-11) days; and this was significantly lower than that in IgG-antibody-negative patients, who had virus shedding duration of 10 (8-12) days (p < 0.05)., Conclusions: Booster immunizations could increase IgG-antibody in patients who have already been infected with the Omicron variant and enhance immune protection. In addition, COVID-19 vaccination may shorten the duration of virus shedding., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2024 Zhen Wan, Jing Han, Deyin Wang, Yonghui Li, Weixiang Zhai, Weikang Zhao, Xiaodong Zhang, Yi Xie.)

Dynamic nuclear polarization (DNP) is a powerful method to enhance nuclear magnetic resonance (NMR) signal intensities, enabling unprecedented applications in life and material science. An ultimate goal is to expand the use of DNP-enhanced solid-state NMR to ultrahigh magnetic fields where optimal spectral resolution and sensitivity are integrated. Trityl-nitroxide (TN) biradicals have attracted significant interest in high-field DNP, but their application to complex (bio)molecules has so far been limited. Here we report a novel postmodification strategy for synthesis of hydrophilic TN biradicals in order to improve their use in biomolecular applications. Initially, three TN biradicals (referred to as NATriPols 1-3) with amino-acid linkers were synthesized. EPR studies showed that the α-position of the amino-acid linkers is an ideal modification site for these biradicals since their electron-electron magnetic interactions are marginally affected by the substituents at this position. On the basis of this finding, we synthesized NATriPol-4 with pyridine disulfide appended at the α-position. Postmodification of NATriPol-4 via thiol-click chemistry resulted in various TN biradicals including hydrophilic NATriPol-5 in a quantitative manner. Interestingly, DNP enhancements at 18.8 T of NATriPols for 13 C, 15 N-proline in a glycerol/water matrix are inversely correlated with their hydrophobicity. Importantly, applications of hydrophilic NATriPol-5 and NATriPol-3 to biomolecules including a globular soluble protein and a membrane targeting peptide reveal significantly improved performance compared to TEMTriPol-1 and AMUPol. Our work provides an efficient approach for one-step synthesis of new polarizing agents with tunable physicochemical properties, thus expediting optimization of new biradicals for biomolecular applications at ultrahigh magnetic fields.

Triarylmethanol adopts a propeller-shaped conformation with either right-handed ( P ) or left-handed ( M ) configuration. Herein, new triarylmethanols with two chiral centers were obtained via introduction of two cis -hydroxyl groups on the side chains, affording four stereoisomers. These four stereoisomers were easily separated by silica gel column chromatography into two pairs of propeller-shaped enantiomers, as shown by NMR and X-ray crystallographic studies. High-performance liquid chromatography (HPLC) studies showed that the configurations of the hydroxyl-bearing triarylmethanols are much more stable than those of the bulky tert -butyldimethylsilyl-protected precursors, inconsistent with the general strategy in which the steric repulsion is largely responsible for the configurational stability. Similarly, two hydroxyl-bearing tetrathiatriarylmethyl (TAM) radicals also exhibit excellent configurational stability and are thus separable by CS-HPLC into four stereoisomers. Interestingly, both helical chirality from triaryl group ( M or P ) and central chirality ( R and S ) on the side chain have little effect on their electron paramagnetic resonance properties. Our present study provides a new strategy to construct configurationally stable triaryl compounds and demonstrates that the side chain on TAM radicals is a new site for their structural modifications.

Aminoethylsulfonate (taurine) is widespread in the environment and highly abundant in the human body. Taurine and other aliphatic sulfonates serve as sulfur sources for diverse aerobic bacteria, which carry out cleavage of the inert sulfonate C-S bond through various O 2 -dependent mechanisms. Taurine also serves as a sulfur source for certain strict anaerobic fermenting bacteria. However, the mechanism of C-S cleavage by these bacteria has long been a mystery. Here we report the biochemical characterization of an anaerobic pathway for taurine sulfur assimilation in a strain of Clostridium butyricum from the human gut. In this pathway, taurine is first converted to hydroxyethylsulfonate (isethionate), followed by C-S cleavage by the O 2 -sensitive isethionate sulfo-lyase IseG, recently identified in sulfate- and sulfite-reducing bacteria. Homologs of the enzymes described in this study have a sporadic distribution in diverse strict and facultative anaerobic bacteria, from both the environment and the taurine-rich human gut, and may enable sulfonate sulfur acquisition in certain nutrient limiting conditions., (© 2019 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Tetrathiatriarylmethyl (TAM, trityl) radicals have found wide applications as spin probes/labels for EPR spectroscopy and imaging, and as polarizing agents for dynamic nuclear polarization. The high hydrophilicity of TAM radicals is essential for their biomedical applications. However, the synthesis of hydrophilic TAM radicals (e.g., OX063) is extremely challenging and has only been reported in the patent literature, to date. Herein, an efficient synthesis of a highly water-soluble TAM radical bis(8-carboxyl-2,2,6,6-tetramethylbenzo[1,2-d:4,5-d']bis([1,3]dithiol-4-yl)-mono-(8-carboxyl-2,2,6,6-tetrakis(2-hydroxyethyl)benzo[1,2-d:4,5-d']bis([1,3]dithiol-4-yl)methyl (TFO), which contains four additional hydroxylethyl groups, relative to the Finland trityl radical CT-03, is reported. Similar to OX063, TFO exhibits excellent properties, including high water solubility in phosphate buffer, low log P, low pK a , long relaxation times, and negligible binding with bovine serum albumin. On the other hand, TFO has a sharper EPR line and higher O 2 sensitivity than those of OX063. Therefore, in combination with its facile synthesis, TFO should find wide applications in magnetic resonance related fields and this synthetic approach would shed new light on the synthesis of other hydrophilic TAM radicals., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The exchange ( J ) interaction of organic biradicals is a crucial factor controlling their physiochemical properties and potential applications and can be modulated by changing the nature of the linker. In the present work, we for the first time demonstrate the effect of chiral configurations of radical parts on the J values of trityl-nitroxide (TN) biradicals. Four diastereoisomers (TNT 1 , TNT 2 , TNL 1 and TNL 2 ) of TN biradicals were synthesized and purified by the conjugation of a racemic ( R / S ) nitroxide with the racemic ( M / P ) trityl radical via l-proline. The absolute configurations of these diastereoisomers were assigned by comparing experimental and calculated electronic circular dichroism (ECD) spectra as ( M , S , S ) for TNT 1 , ( P , S , S ) for TNT 2 , ( M , S , R ) for TNL 1 and ( P , S , R ) for TNL 2 . Electron paramagnetic resonance (EPR) results showed that the configuration of the nitroxide part instead of the trityl part is dominant in controlling the exchange interactions and the order of the J values at room temperature is TNT 1 (252 G) > TNT 2 (127 G) ≫ TNL 2 (33 G) > TNL 1 (14 G). Moreover, the J values of TNL 1 /TNL 2 with the S configuration in the nitroxide part vary with temperature and the polarity of solvents due to their flexible linker, whereas the J values of TNT 1 /TNT 2 are almost insensitive to these two factors due to the rigidity of their linkers. The distinct exchange interactions between TNT 1,2 and TNL 1,2 in the frozen state led to strongly different high-field dynamic nuclear polarization (DNP) enhancements with ε = 7 for TNT 1,2 and 40 for TNL 1,2 under 800 MHz DNP conditions.