PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2022
·Vol. 24
·期 39
·24535-24541
·
IF 3.945
Lu Qian,Xin Guo,Kai Zhang,Miao Yu
Water is essential in the evolution of life and plays an important role in the structure and function of the basic substances of life, such as protein and DNA. However, the specific details of the role of water with respect to chitin, the most abundant biomacromolecule on Earth after cellulose, remain unclear. In this study, atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) was used to explore the effects of hydrogen bonds (H-bonds) on the single-molecule mechanics of chitin. Comparative experiments showed that a single chitin chain exhibited the same single-chain natural elasticity as cellulose in nonane, indicating that a single chitin chain can form strong intrachain H-bonds in nonane. Moreover, the single-chain elasticity of chitin obtained in dimethyl sulfoxide (DMSO) was consistent with that of cellulose, and both superposed well with the theoretical model (QM-FJC) to show the single-chain elasticity of the chitin/cellulose backbone, indicating that DMSO can eliminate almost all the intrachain H-bonds of single chitin chains. However, when water was introduced as the surrounding environment, the intrachain H-bonds of chitin were found to be weaker than those of cellulose, which is supported by the AFM mapping results. Single-molecule studies reveal that water is a unique solvent for chitin, and the nanomechanics and hydrophobicity of chitin can be influenced by an external solvent (water in this work) through regulation of the intrachain H-bonds. The present study casts new insight into the role of H-bonds and water in the structures and functions of polysaccharides.
研究领域:
生物物理学
·
分子生物学
✓ 已验证
DOI
高影响因子
SENSORS
·
2017
·Vol. 17
·期 4
·811
·
IF 2.677
Wei-Qiong Li,Bing Huang,Miao-Ling Huang,Lin-Lu Peng,Ze-Wen Hong,Ju-Fang Zheng,Wen-Bo Chen,Jian-Feng Li,Xiao-Shun Zhou
The single molecular conductance of amino acids was measured by a scanning tunneling microscope (STM) break junction. Conductance measurement of alanine gives out two conductance values at 10−1.85G0(1095 nS) and 10−3.7G0(15.5 nS), while similar conductance values are also observed for aspartic acid and glutamic acid, which have one more carboxylic acid group compared with alanine. This may show that the backbone of NH2–C–COOH is the primary means of electron transport in the molecular junction of aspartic acid and glutamic acid. However, NH2–C–COOH is not the primary means of electron transport in the methionine junction, which may be caused by the strong interaction of the Au–SMe (methyl sulfide) bond for the methionine junction. The current work reveals the important role of the anchoring group in the electron transport in different amino acids junctions.Keywords:amino acid;single-molecule junction;STM break junction;carboxylic acid;amine
研究领域:
生物物理学
·
分子电子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 4
·2294-2300
·
IF 3.9
Lu Qian,Kai Zhang,Xin Guo,Miao Yu
Chitin and chitosan are important support structures for many organisms and are important renewable macromolecular biomass resources. Structurally, with the removal of acetyl group, the solubility of chitosan is improved. However, the specific mechanism of solubility enhancement from chitin to chitosan is still unclear. In this study, the atomic force microscopy (AFM)-based single molecule force spectroscopy (SMFS) was used to obtain the single-chain mechanical behavior of chitin and chitosan. The results show that the hydrogen (H)-bonds' state, which can be influenced by the solvent, determines the degree of binding water (solubility) of polysaccharides, and that the binding water energy of a single chitosan chain is 6 times higher than that of chitin in water. Thus, H-bonding is the key to solubility enhancement and can be used to modulate the solubility properties of chitosan. It is expected that our studies can help to understand the structural and functional properties of chitin and chitosan at the single molecule level.
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYHEDRON
·
2022
·
IF 2.975
Na Qiao,Xiao-Xiao Li,Ying Chen,Xiao-Yan Xin,Chen Yang,Shan-Shan Dong,Yan-Zi Wang,Xing-Jin Li,Yu-Peng Hua,Wen-Min Wang
Three dinuclear Ln 2 compounds, [Ln 2 (dbm) 4 (L - ) 2 ]·4CH 3 CN (Ln = Gd ( 1 ), Tb ( 2 ), Dy ( 3 ), HL = (E)-N'-(2-hydroxybenzylidene)benzohydrazide and dbm = dibenzoylmethane), have been obtained by a solvent evaporation method. The structural analyses indicate that the three Ln 2 compounds (Gd 2 , Tb 2 and Dy 2 ) are isostructural with a Ln 2 O 2 center. Magnetic investigations show the presence of magnetic refrigeration in the Gd-based compound with a -ΔS m value of 17.62 J kg −1 K −1 ( T = 2.0 K and Δ H = 7.0 T); for compound 3 , however, single-molecular magnet behavior (SMM) was observed ( U eff /k B = 0.84 K and τ 0 = 1.08 × 10 −5 s).
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Chemistry
·
2020
·
IF 3.693
Ai Qiushuang,Fu Qiang,Liang Feng
Recognition tunneling technique owns the capability for investigating and characterizing molecules at single molecule level. Here, we investigated the conductance value of cucurbit[7]uril (CB[7]) and melphalan@CB[7] (Mel@CB[7]) complex molecular junctions by using recognition tunneling technique. The conductances of CB[7] and Mel@CB[7] with different pH values were studied in aqueous media as well as organic solvent. Both pH value and guest molecule have an impact on the conductance of CB[7] molecular junction. The conductances of CB[7] and Mel@CB[7] both showed slightly difference on the conductance under different measurement systems. This work extends the molecular conductance measurement to aqueous media and provides new insights of pH-responsive host-guest system for single molecule detection through electrical measurements.
研究领域:
生物物理学
·
纳米科学
·
分子电子学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2025
·
IF 3.1
Zeling Guo,Yu Meng,Xinyu Li,Jiangting Li,Shang Zhou,Rongrong Feng,Weiting Wu,Mingjing Xu,Jinhao Liu,Xiangfu Zeng,Weidong Zhao,Haijian Zhong
Hepatocellular carcinoma (HCC) is a serious concern worldwide. The published reports showed that aberrant CD95 receptor expression plays a critical role in apoptosis in liver cancer. While curcumin has shown promise in inducing apoptosis in liver cancer cells, its direct effects on CD95 expression during this process have not been thoroughly investigated. This study aims to quantitatively assess the expression of the CD95 receptor in HepG2 cells treated with different concentrations of curcumin using techniques such as fluorescence staining, single-molecule force spectroscopy (SMFS), and single-molecule recognition imaging (SMRI). Fluorescence staining results indicate a significant increase in CD95 expression following curcumin treatment. For the first time, SMFS and SMRI techniques were used to directly reveal the binding sites of CD95 on the cell membrane, with the number of binding sites increasing as the curcumin concentration increased. Additionally, the binding force between an antibody-modified probe and CD95 was strengthened with curcumin treatment, suggesting that curcumin enhances both the quantity and affinity of CD95 binding sites. This study provides new insights into curcumin-induced CD95-mediated apoptosis in liver cancer cells and highlights the potential of AFM techniques for investigating drug mechanisms. Overall, these findings may inform innovative therapeutic strategies for liver cancer and improve drug design processes.
研究领域:
肿瘤学
·
分子生物学
·
药理学
✓ 已验证
DOI
PubMed
高影响因子
SURFACE AND INTERFACE ANALYSIS
·
2022
·Vol. 54
·期 10
·1087-1097
·
IF 1.702
Jiekai Feng,Faze Chen,Jiaqi Chao,Zexin Cai,Teng Liu,Du Zhang,Yanling Tian
Copper mesh (CM) is one of the most commonly used engineering materials due to its remarkable mechanical and electromagnetic properties. However, CMs are generally susceptible to chemical corrosion in harsh environments, which greatly limits their long-term usage. In this paper, we come up with a one-step perfluorodecanethiol self-assembly means to manufacture superhydrophobic CM with significantly improved anti-corrosion property. The self-assembly reaction between copper and 1 H ,1 H ,2 H ,2 H -perfluorodecanethiol created nanoscale rough structures and lowered the surface energy of the CM surface, which was account for the excellent repellence towards various aqueous solutions. The electrochemical tests demonstrated that, compared with original CM, the i corr value of the self-assembled monolayers (SAMs) functionalized CM decreases about one order of magnitude, whereas the corrosion protection efficiency of the treated CM in NaCl, NaOH, and HCl aqueous solutions were all obviously increased. Therefore, the proposed simple method could be an alternative candidate for the creation of functional CM with anti-corrosion properties that could be used under complex conditions.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2021
·
IF 3.196
Jingyan Zhu,Baolin Liu,Weibing Zhang,Jun Jiang,Xinhua Li
Single-molecule magnets in cobalt clusters is much less well known than it is in manganese(II)/(III)/(IV) clusters. To explore new types of cobalt clusters and their potential applications, a new mixed valence coordination polymer ([Co(III) 3 Co(II) 2 (mba) 6 (Hdtba) (H 2 O) 4 ] n , H 2 dtba=2,2’-dithiodibenzoic acid, H 2 mba=2-mercaptobenzoic acid) ( 1 ) is constructed by employing cobalt chloride hexahydrate and H 2 mba as starting reactants under hydrothermal conditions. Single-crystal XRD studies indicate that 1 consists of a trinuclear cobalt(III)-sulfur cluster moiety and two discrete cobalt(II) nodes, which result in the formation of a covalent three-dimensional complex network. Similarly, the cobalt(III) cluster moiety acts as a building unit in this infinite coordination polymer 1 instead of the discrete and tiara-like clusters previously reported in the literature. Magnetic studies show its slow magnetic relaxation in the absence of an applied dc field, which is characteristic behavior of single-ion magnets, caused by the individual Co(II) ions.
研究领域:
无机化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Jianfeng Li,Wei Cao,Jinjin Li,Ming Ma
Hypothesis Achievement of superlubricity is an effective method to reduce friction and wear, which has a prominent influence on the operational efficiency and lifetime of a device. However, some burning issues still remain to be solved for the practical applications of superlubricity, such as the poor load-bearing capacity, especially in liquid superlubricity. Therefore, exploring an effective method to enhance the superlubricity performance is essential to accelerate the application of superlubricity. Experiments The friction properties between two different self-assembled monolayers (SAMs)—a perfluorocarbon SAM and a hydrocarbon SAM—and graphite in water were explored and compared by atomic force microscopy (AFM). Findings Enhanced superlubricity performance due to the fluorination was observed. Specifically, we observed an approximately 85% reduction of the friction coefficient after fluorination, and superlubricity was achieved with extremely low friction coefficient of 0.0003. Moreover, 2.4-fold greater load-bearing capacity of the superlubricity was obtained after fluorination. The molecular origin of the superlubricity enhancement by fluorination was revealed by molecular dynamics (MD) simulations, indicating that the greater load-bearing capacity of the perfluorocarbon SAM was ascribed to the enhanced interaction between the water and SAM by fluorination to form a more robust layered water structure confined in the contact zone, which played a pivotal role in the superlubricity.
研究领域:
材料科学
·
表面科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CORROSION SCIENCE
·
2016
·
IF 5.154
Yinzhe Yu,Yizhen Wang,Jin Li,Daquan Zhang,Lixin Gao
The self-assembled monolayer (SAMs) of 2-(1-tosyl-1H-1,2,3-triazol-4- yl ) propan-2-ol (TTP) was in-situ assembled on copper surface via click chemistry reaction between 2, 2-dimethylethynyl carbinol (MBY) and tosyl azide (TA). The electrochemical results indicate that the click-assembled TTP film can strongly suppress the corrosion reaction of copper in 3 wt.% NaCl and its protection efficiency is 93.6%. Polarization curves show that TTP SAMs is an anodic passivation type inhibitor. The adsorption of TTP molecules on Cu 2 O (0 0 1) surface is in the flat orientation of the nearby triazole ring and O atoms.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ACS Nano
·
2025
·
IF 16
Jinyang Liu,Xuebo Zhang,Bingjie Zhao,Huan Ling,Yanzhong Li,Kuangshi Sun,Song Chen,Yanxin Zhang,Tianli Zhai,Yunxiang Zhang,Fuyou Li,Qian Liu
Single-molecule tracking offers nanometer resolution for studying individual molecule dynamics but is often limited by sparse labeling to avoid signal overlap. We present Red-Light-Activated Single-molecule Tracking (RE-LAST) strategy to address this challenge utilizing a photoactivatable probe, SiR670. SiR670 combines traditional silicon rhodamine with a photocage called SO, quenching fluorescence via photoinduced electron transfer (PET). Red light triggers SiR670 excitation, generating singlet oxygen that oxidizes the SO cage, halting PET and restoring fluorescence. RE-LAST used red light for both activation and imaging, eliminating harmful UV exposure. This method enables high-throughput single-molecule tracking, achieving approximately 9 times more tracks than conventional methods and allowing detailed classification of CD56 membrane protein motion. Furthermore, in situ imaging of single live cells revealed the effects of triplet quencher and oxygen scavenging system (OSS) on membrane protein dynamics. While triplet quenchers like Trolox had minimal impact on protein movement patterns, OSS significantly accelerated protein movement and increased the proportion of mobile proteins. This approach provides a comprehensive method for investigating membrane protein dynamics in living cells, contributing to further developments in cellular and molecular biology.
研究领域:
细胞生物学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2019
·Vol. 9
·期 9
·477
·
IF 2.061
Qian-Jun Deng,Min Chen,Dong-Chu Chen,Chang-Ai Chen
The organic ligand (1-methyl-1H-benzo[d]imidazol-2-yl)methanol (HL) was used to react with CoX2·6H2O (X = Cl and Br) under solvothermal conditions to obtain the complex [Co4(L)6(X)2] (1, X = Cl; 2, X = Br). The butterfly-shaped structure of complex 1 and 2 suggest that Co(II) ions have two different coordinated modes, which are five coordination with O3NX environment and six coordination with O4N2environment. In addition, the electrospray ionization mass spectrometry (ESI-MS) analysis indicated that the ion molecular fragment of highest intensity was [Co4(L)6]2+, and there existed a high nuclear fragment peak of [Co7(L)12]2+. Interestingly, it was basically completely transformed into [Co7(L)12]2+two days later, so those two complexes were relatively stable in CH3OH. Magnetic characterization exhibited that complex 1 and 2 display field-induced single-molecule magnetic behavior, of which the energy hillsUeff/kBwere 28 and 20 K under direct-current field of 0.1 T, respectively.Keywords:tetranuclear;butterfly shaped;mass spectrometric;single-molecule magnet (SMM)
研究领域:
无机化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）