JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2024
·
IF 8
Shinan Wang,Yue Yuan,Erping Bi
Coexisting tetracycline (TC), dissolved organic matter (DOM), and metal cations in aqueous environments might form complexes and consequently affect the environmental fate of TC. In this study, the interactions among coexisting humic acid (HA), TC, and Mg(II) in solutions were investigated by equilibrium dialysis batch experiments and nuclear magnetic resonance hydrogen spectroscopy ( 1 H NMR) characterization. In the binary systems, the dimethylamine (4Me 2 NH + ) functional group on the A-ring of TC bound to the oxygen-containing functional groups of HA via hydrogen bond. The solution pH affected the agglomeration morphology and dissociation of the oxygen-containing functional groups of HA as well as protonation and spatial conformation of TC, which in turn affected the HA-TC interactions. The complexation sites and ratio of Mg(II) on TC affect the binding mode in the ternary system. When the TC-Mg(II) complexation ratio is 1:1, the B, C, and D rings of TC preferentially complex with Mg(II), resulting in the change of TC from an extended to a twisted conformation. At this time, Mg(II) had a weaker inhibitory effect on binding affinity between HA and TC. When the complexation ratio was 1:2, the second Mg(II) complexation deactivated the 4Me 2 NH + on the A ring and further stabilized TC twisted conformation, resulting in a stronger inhibitory effect on the binding of TC to HA. Under acidic conditions, the solution pH mainly caused the difficulty in forming TC-Mg(II) complexes. The inhibitory effect of Mg(II) on the binding between HA and TC is weaker than that under alkaline conditions.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2024
·Vol. 16
·期 7
·995
·
IF 4.7
Song Zhang,Yunxu Ji,Yiwei He,Juan Dong,Haohang Li,Shirui Yu
Chitin and chitosan are important structural macromolecules for most fungi and marine crustaceans. The functions and application areas of the two molecules are also adjacent beyond their similar molecular structure, such as tissue engineering and food safety where solution systems are involved. However, the elasticities of chitin and chitosan in solution lack comparison at the molecular level. In this study, the single-molecule elasticities of chitin and chitosan in different solutions are investigated via atomic force microscope (AFM) based single-molecule spectroscopy (SMFS). The results manifest that the two macromolecules share the similar inherent elasticity in DOSM due to their same chain backbone. However, obvious elastic deviations can be observed in aqueous conditions. Especially, a lower pH value (acid environment) is helpful to increase the elasticity of both chitin and chitosan. On the contrary, the tendency of elastic variation of chitin and chitosan in a larger pH value (alkaline environment) shows obvious diversity, which is mainly determined by the side groups. This basic study may produce enlightenment for the design of intelligent chitin and chitosan food packaging and biomedical materials.
研究领域:
生物材料学
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分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Haichang Yang,Erfa Ding,Fanfan Zhang,Yaowen Xing,Xiahui Gui,Yijun Cao
Interface nanobubbles (INBs) have potential applications in various fields, and their existence has been adequately demonstrated. However, the stability and geometric morphology of INBs in complex solution environments remain less clear. In this study, we investigated the stability and geometrical characteristics of INBs exposed to various solution environments both in situ and statistically. We find that INBs in a 40 vol% ethanol-water solution exhibits a decrease in width but an increase in height and contact angle (from the gas side). In cationic, anionic, and nonionic surfactant solutions, the height of INBs tends to increase, accompanied by a reduction in width, resulting in an increase in the contact angle. The observed increase in height may be attributed to the expansion of INBs, which is likely caused by a reduction in surface tension. This suggests that the gas-liquid interface of INBs remains unsaturated by organic moieties in both pure water and solutions of low surfactant concentrations. The increase in contact angle when INBs are exposed to solutions with a lower liquid-gas interfacial tension is contrary to expectations, which may be caused by the increased solid-gas interfacial tension. However, in different concentrations of NaCl solution, the INBs remain stable with minimal changes in their geometrical parameters. Furthermore, the experimental results demonstrate that INBs exhibit strong stability under lateral shear force and strong vertical pressure. The findings of this study contribute to a deeper understanding of the INBs and provide theoretical support for applications related to INBs.
研究领域:
物理化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN TOXICOLOGY
·
2021
·
IF 3.739
Jiaxing He,Mingyue Liu,Lingfeng Yin,Ziqi Deng,Junhong Pang,Haoxian He,Li Dang,Ming-De Li
Carprofen (CP), one kind of a nonsteroidal anti-inflammatory drug, exhibits phototoxic side effects in physiology, while its phototoxic mechanism is ambiguous. To uncover CP’s photophysical and photochemical reaction processes, femtosecond to nanosecond transient absorption spectroscopies were employed to directly detect excited states and transient intermediates of CP upon UV irradiation in pure acetonitrile (MeCN), MeCN/water 1:1, and acid/alkaline buffer solutions. The transient absorption data together with DFT calculations were integrated to elucidate mechanisms for photochemical reactions of CP in different solutions. The associated photophysical and photochemical reaction pathways are dependent on various solution environments. In a pure MeCN solvent, CP is excited to a singlet state (S1) and rapidly interacts with the solvent to proceed solvent rearrangement (SR). It then undergoes vibrational cooling (VC) and proceeds intersystem crossing (ISC) to produce the lowest triplet state (3CP). 3CP finally decays to the ground state. While in a MeCN/water 1:1 solution, deprotonated S1 of CP experiences SR and VC processes, and then it is promoted to a deprotonated triplet state (3CP–). 3CP– undergoes the parallel reactions: dechlorination to a phenyl radical (2CP–) and decarboxylation to a T1 anion (3CP–(de-CO2)). Finally, both intermediates produce the radical anion species 2CP–(de-CO2). In a pH = 7.4 (MeCN/PBS 1:1) solution, 3CP– can be converted into 2CP–(de-CO2) more quickly. Interestingly, we found that the dechlorination step can be promoted in an alkaline solution. Phenyl and chlorine radicals produced in an aqueous solution may be the root cause of the drug’s harmful side effects on the human body. This may be useful to guide the design of related CP drugs with minimal phototoxicity in the pharmaceutical process.
研究领域:
药理学
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光化学
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理论化学
✓ 已验证
DOI
PubMed
高影响因子
Nano Research
·
2019
·Vol. 12
·期 7
·1643-1649
·
IF 8.515
Liu Yang,Tian Xiaorui,Guo Weiran,Wang Wenqiang,Guan Zhiqiang,Xu Hongxing
Integrating surface enhanced Raman scattering with microfluidics is the long-term goal for reduced volume, multiplex and automation fingerprint detection of biomolecules. High sensitivity, repeatability, stability, reusability and real-time detection are the performance goals of Raman detection in the aqueous solution environment. Here, we reported the study on cavity mode enhanced SERS detection of both surface-adsorbed molecules and non-surface-adsorbed molecules in the solution environment. The cavity modes had important influence on the SERS enhancement, especially for the non-surface adsorbed molecules. Uniform, repeatable, reusable and real-time Raman signal detection of the non-surface adsorbed Rhodamine 6G molecules was demonstrated. Our work is an important step for the practical on-chip microfluidic Raman detection applications.
研究领域:
生物分析
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光学检测
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微流控技术
✓ 已验证
产品关联
DOI
高影响因子
Science Advances
·
2025
·Vol. 11
·期 39
·
IF 12.5
Chenchen Wu,Shiyu Yang,Kebo Zeng,Xiaokang Dai,Yu Duan,Shu Zhang,Puyi Ma,Xiangdong Guo,Shuang Zhang,Xiaoxia Yang,Qing Dai
Quantifying nanoscale protein secondary structure in aqueous solutions is crucial for understanding protein interactions and dynamics. Deep learning models are adept at predicting protein secondary structures, but their ability to model them in aqueous solutions is hindered by data constraints. Here, we present a mid-infrared plasmonic sensor integrated with a synthesized complex-frequency wave (s-CFW)–informed convolutional neural network (CNN) to address these limitations. The sensor enables direct probing of the amide I band in sub-10-nanometer proteins. By using s-CFW to amplify target spectral features, the developed physics-informed CNN achieves a mean relative error of less than 0.1 in predicting secondary structure percentages, more than twice as accurate as a pristine CNN. This method enables in situ and real-time quantification of subtle conformational changes during protein assembly, thereby addressing the issue of data scarcity that now hinders the development of advanced deep learning models for predicting protein dynamics and interactions in physiological environments.
研究领域:
生物物理学
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分子生物学
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生物医学工程
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纳米生物技术
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蛋白质科学
✓ 已验证
DOI
PubMed
高影响因子
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