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
MACROMOLECULES
·
2024
·
IF 5.1
Xin Liu,Ruixiang Yao,Zhe Sun,Houyu Zhang,Feng Yan,Hongbin Li,Wenke Zhang
The host–guest recognition of crown ethers and alkali metal ions plays a key role in many functional systems. The understanding of the static conformation of the crown ether ring and guest ion is steadily growing, but little is known about the dynamic response of the complex structure when the crown ether ring is deformed. In this study, we successfully monitored the conformational changes of the host–guest complex formed by poly(dibenzo-18-crown-6) and metal ions through single-molecule force spectroscopy and constrained geometry simulated external force calculations. A distinctive shoulder-like force plateau can be observed on the force–extension curve, which depends on both the cation and anion species. Quantum chemical calculations revealed that during the conformation change, the number of coordination bonds between the oxygen atoms on the ring and K+ ions were dynamically changed from six to four with an intermediate bond number of two, and K+ was gradually squeezed out of the center of the crown ether ring. In addition, the size of the alkali metal ions was found to greatly affect its deformation pathway. This study deepened our understanding of crown ether-based host–guest interactions in a brand-new vision. And, it is useful for tuning the properties of crown ether-based functional materials because the DB18C6 unit can be easily incorporated into the network of polymer materials. Furthermore, such a method can be used to explore and tune the host–guest interactions in other macrocycle-based systems.
研究领域:
化学
·
材料科学
·
生物物理学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Yifan Chen,Wentao Yuan,Yingxin Zhang,Hu-jun Qian,Zhong-yuan Lu,Shuxun Cui
According to the principle of polymer science, the gelation process of κ-carrageenan should start with polymer chains in a disordered coil conformation. However, the coil-helix model has been challenged by recent studies, which pointed out that in deionized water, κ-carrageenan exists in single-helix conformation rather than random coil. Here, we employ single-molecule force spectroscopy (SMFS) to investigate its conformation under different conditions at the single-chain level. Direct evidence for the existence of random coil state is obtained. In addition, it is found that coil-single helix transition can be induced by external Na + ions, which can screen the charges of the sulfated groups in κ-carrageenan. Thus, the mechanism of the first step of κ-carrageenan gelation is revealed, which lays a solid foundation for better understanding of the entire gelation process.
研究领域:
高分子科学
·
生物物理学
·
食品科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2018
·
IF 3.483
Yaqian Guo,Ruoyu Zhang,Qiang Xiao,Hongxia Guo,Zongbao Wang,Xing Li,Jing Chen,Jin Zhu
Four chain extenders, 1,3-propanediol (PDO), 2-methyl-1,3-propanediol (MPO), 2,2-dimethyl-1,3-propanediol (NPG) and 2,2,4,4-tetramethyl-1,3-cyclobutanedio (CBDO) are chosen to synthesize model polyurethanes , respectively. Although with similar oxygen distance between the two hydroxyl groups , their volumes increase gradually according to computer simulation. As expected, the degree of microphase separation decreases with the increasing chain extender volume. Except for CBDO based polyurethane, the other three samples show systematic variations in mechanical properties . Various techniques including single-molecule force spectroscopy (SMFS), small-angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR) are employed to investigate the structural changes after tensile break in different length scales. A picture of asynchronous fracture of microstructures during the tensile break of thermoplastic polyurethane elastomers can be obtained by the combination of different analytical methods. It is interesting to note that the macroscopic break may not affect the state of hydrogen bonding or the hard phase network. Sometimes, the hydrogen bonding state changes a lot while the phase network keeps almost the same, or vice versa.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 19
·6769
·
IF 4.6
Song Zhang,Miao Yu,Guoqiang Zhang,Guanmei He,Yunxu Ji,Juan Dong,Huayan Zheng,Lu Qian
Chitin is one of the most common polysaccharides and is abundant in the cell walls of fungi and the shells of insects and aquatic organisms as a skeleton. The mechanism of how chitin responds to pH is essential to the precise control of brewing and the design of smart chitin materials. However, this molecular mechanism remains a mystery. Results from single-molecule studies, including single-molecule force spectroscopy (SMFS), AFM imaging, and molecular dynamic (MD) simulations, have shown that the mechanical and conformational behaviors of chitin molecules show surprising pH responsiveness. This can be compared with how, in natural aqueous solutions, chitin tends to form a more relaxed spreading conformation and show considerable elasticity under low stretching forces in acidic conditions. However, its molecular chain collapses into a rigid globule in alkaline solutions. The results show that the chain state of chitin can be regulated by the proportions of inter- and intramolecular H-bonds, which are determined via the number of water bridges on the chain under different pH values. This basic study may be helpful for understanding the cellular activities of fungi under pH stress and the design of chitin-based drug carriers.Keywords:chitin;single-molecule force spectroscopy;molecular dynamic simulations;non-covalent interactions;elasticity
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
LANGMUIR
·
2024
·
IF 3.7
Miao Yu,Xin Guo,Kai Zhang,Xiaomin Kang,Song Zhang,Lu Qian
Hyaluronic acid (HA), a vital glycosaminoglycan in living organisms, possesses remarkable mechanical and viscoelastic properties that have garnered significant attention in therapeutic, biomedical, and cosmetic applications. However, a comprehensive picture of the physicochemical and biocharacterization of HA at the single-molecule level remains elusive. In this work, atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) and molecular dynamics (MD) simulation were used to investigate the nanomechanics and water retention properties of HA at the single-molecule level. The present study aims to unravel the intricate details of the influence of molecular structure on HA behavior and shed light on its unique attributes. According to the force measurements, the energy used to stretch a HA chain in water is 8.45 kJ/mol, significantly surpassing that of Curdlan (3.45 kJ/mol) and chitin (2.23 kJ/mol), both of which possess molecular structures partially similar to that of HA. Intriguingly, the strength of the intrachain interaction of HA (5.54 kJ/mol) was considerably weaker compared to Curdlan (11.06 kJ/mol) and chitin (or cellulose, 10.76 kJ/mol). This result indicates that HA exhibits a preference for interacting with water rather than with itself, thereby showing enhanced water affinity. Moreover, the force measurements demonstrated that changing the glycosidic bond from β-(1–3) (Curdlan) or β-(1–4) (chitin or cellulose) to β-(1–3) + β-(1–4) (HA) resulted in polysaccharides displaying improved water affinity and more extended conformation. These conclusions were further verified by molecular dynamics (MD) simulations. Overall, our work sheds new light on the nanomechanics and water retention properties of HA at the single-molecule level, offering valuable insights for future research in this field.
研究领域:
生物物理学
·
生物材料学
·
纳米科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR RECOGNITION
·
2019
·Vol. 33
·期 5
·e2829
·
IF 1.919
Shaoyuan Li,Yan Zheng,Yaqin Liu,Xiuhua Geng,Xiaofeng Liu,Liyuan Zou,Qing Wang,Xiaohai Yang,Kemin Wang
Understanding the binding of split aptamer/its target could become a breakthrough in the application of split aptamer. Herein, vascular endothelial growth factor (VEGF), a major biomarker of human diseases, was used as a model, and its interaction with split aptamer was explored with single molecule force spectroscopy (SMFS). SMFS demonstrated that the interaction force of split aptamer/VEGF 165 was 169.44 ± 6.59 pN at the loading rate of 35.2 nN/s, and the binding probability of split aptamer/VEGF 165 was dependent on the concentration of VEGF 165 . On the basis of dynamic force spectroscopy results, one activation barrier in the dissociation process of split aptamer/VEGF 165 complexes was revealed, which was similar to that of the intact aptamer/VEGF 165 . Besides, the dissociation rate constant ( k off ) of split aptamer/VEGF 165 was close to that of intact aptamer/VEGF 165 , and the interaction force of split aptamer/VEGF 165 was higher than the force of intact aptamer/VEGF 165 . It indicated that split aptamer also possessed high affinity with VEGF 165 . The work can provide a new method for exploring the interaction of split aptamer/its targets at single-molecule level.
研究领域:
生物物理学
·
分子生物学
·
医学诊断
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Zhirong Li,Lulu Zhang,Zhanzhong Wang,Xiongli Kang,Huiying Jin,Wenjie Zhao,Jun Zhang,Haiquan Su
Identification of the phosphatidylserine (PS) discrepancies occurring on the cellular membrane during apoptotic processes is of the utmost importance. However, monitoring the quantity of PS molecules in real-time at a single-cell level currently remains a challenging task. Here, we demonstrate this objective by leveraging the specific binding and reversible interaction exhibited by the zinc(II) dipyridinamine complex (ZnDPA) with PS. Lipoic acid-functionalized ZnDPA (LP-ZnDPA) was subsequently immobilized onto the surface of an atomic force microscopy cantilever to form a force probe, ALP–ZnDPA, enabling a PS-specific dynamic imaging and detection mode. By utilizing this technique, we can not only create a heat map of the expression level of PS with submicron resolution but also quantify the number of molecules present on a single cell’s surface with a detection limit of 1.86 × 104 molecules. The feasibility of the proposed method is demonstrated through the analysis of PS expression levels in different cancer cell lines and at various stages of paclitaxel-induced apoptosis. This study represents the first application of a force probe to quantify PS molecules on the surface of individual cells, providing insight into dynamic changes in PS content during apoptosis at the molecular level and introducing a novel dimension to current detection methodologies.
研究领域:
生物物理学
·
分子生物学
·
细胞生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMACROMOLECULES
·
2025
·
IF 5.4
Jiahui Yang,Zhiyuan Wang,Zepeng Li,Haoyang Xu,Bin Xue,Yi Cao,Zhaojie Li,Yiran Li
3,4-Dihydroxyphenylalanine (DOPA) has inspired the development of artificial adhesives, but efforts to enhance its adhesion strength and durability continue to evolve. However, it is tough work to improve DOPA wet adhesion by chemically decorating DOPA itself, despite the potential benefit of a concise and high-quality adhesion unit. Here, we synthesized a series of DOPA substituents by introducing different electron-withdrawing groups at the ortho position of the phenyl ring. This modification allowed us to effectively control the adhesion and antioxidation properties of DOPA. Combining atomic force microscopy (AFM)-based single-molecule force spectroscopy (SFMS) and cyclic voltammetry, we comprehensively investigated DOPA’s antioxidation and adhesion capabilities. We found that adding a chlorine or bromine atom to the catechol ring significantly increases the DOPA wet adhesion strength. Additionally, halogen-substituted DOPA exhibited greater stability than dopamine in liquid solutions. Notably, chlorine-substituted DOPA maintained a strong adhesion ability even in salt water, offering potential benefits for bioadhesive applications.
研究领域:
材料科学
·
化学
·
生物黏合剂
·
表面科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry Letters
·
2023
·
IF 5.7
Tianyu Cai,Jiaqing Zhang,Jingjing Deng,Qinman Tian,Ruoqi Zhang,Haokai Geng,Yuedong Liu,Keding Zhong,Liting Wen,Chunxiang Liu,Xun Hu,Yuehui Li,Zhipeng Li,Shipeng Hao,Kai Yang,Huizhong Xu
DNA alkylating agents are widely used in anticancer pharmacology. Although shown to induce cross-linking and/or methylation of DNA, how they affect the mechanical properties of DNA and activity of DNA enzymes remains to be elucidated. Here, we perform single-molecule optical tweezer experiments on DNA treated with alkylating agents, including melphalan, cisplatin, and dacarbazine. While all three drugs induce a significant increase of overstretching force and a reduction of hysteresis, suggesting stabilization of DNA against shearing forces, their effects on elasticity of DNA were quite different, with the largest change in persistence length induced by cisplatin. Furthermore, we find that these alkylating-agent-induced changes on DNA have different effects on processivity of DNA polymerase, with melphalan and cisplatin showing significantly reduced activity and dacarbazine showing little effect. Overall, our results provide new insights into the effects for these alkylating agents, which could potentially facilitate a better design of related drugs.
研究领域:
生物化学
·
生物物理
·
分子生物学
·
药理学
·
癌症研究
✓ 已验证
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2022
·
IF 9.879
Shengdao Wang,Shuwen Zhang,Yanchao Yang,Zhongxin Dong,Guibin Wang
Electrochemical grafting of diazonium salts have been applied to improve interfacial properties of carbon fiber and matrix resin . However, these graft modifications are still limited to general-purpose carbon fiber reinforced resin matrix composites such as epoxy. In this research, the direct grafting of Poly (aryl ether ketone) (PAEK) macromolecule on carbon fiber was achieved with mild condition. Firstly, aniline was introduced into Poly (ether ether ketone) (PEEK) as pendent group to improve solubility and amino terminated group was introduced as precursor of diazonium salt. Then the graft was conduct through diazonium salt reduction. After modification, the aniline side group could be hydrolyzed off to recover crystallinity . To further analyze the graft, single molecular-force spectroscopy was introduced to investigate the surface of carbon fiber. Impressively, the extension curve suggested the PAEK macromolecule had been attached to surface through strong interaction. Combined this with XPS data, it was believed that the graft was a success. As a result, the grafted polymer along with the polymer that physically absorbed on carbon fiber in electrolyte can cooperate to strengthen the interface. The interfacial shear strength of the grafted carbon fiber and PEEK increased from 42.27 MPa to 97.33 MPa by 130.26%. The improvement mainly originated from the covalent bonding that connected the carbon fiber and the graft coating layer as well as the great compatibility between the graft coating layer and the matrix resin. These results also demonstrated the possibility to graft high performance polymers on carbon fiber through one-step modifications.
研究领域:
材料科学
·
聚合物化学
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
RSC Chemical Biology
·
2022
·Vol. 3
·期 10
·1276-1281
·
IF 0
Xuan Ding,Ziyi Wang,Bin Zheng,Shengchao Shi,Yibing Deng,Hanyang Yu,Peng Zheng
Enzymatic protein ligation has become the most powerful and widely used method for high-precision atomic force microscopy single-molecule force spectroscopy (AFM-SMFS) study of protein mechanics. However, this methodology typically requires the functionalization of the glass surface with a corresponding peptide sequence/tag for enzymatic recognition and multiple steps are needed. Thus, it is time-consuming and a high level of experience is needed for reliable results. To solve this problem, we simplified the procedure using two strategies both based on asparaginyl endopeptidase (AEP). First, we designed a heterobifunctional peptide-based crosslinker, GL-peptide-propargylglycine, which links to an N3-functionalized surface via the click reaction. Then, the target protein with a C-terminal NGL sequence can be immobilized via the AEP-mediated ligation. Furthermore, we took advantage of the direct ligation between primary amino in a small molecule and protein with C-terminal NGL by AEP. Thus, the target protein can be immobilized on an amino-functionalized surface via AEP in one step. Both approaches were successfully applied to the AFM-SMFS study of eGFP, showing consistent single-molecule results.
研究领域:
生物化学
·
生物物理学
·
分子生物学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
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