LANGMUIR
·
2022
·
IF 4.331
Chu Wang,Yong-Hao Ma,Xiaofeng Han,Xiaolin Lu
Aurein 1.2 (Aur), a highly efficient 13-residue antimicrobial peptide (AMP) with a broad-spectrum antibiotic activity originally derived from the Australian frog skin secretions, can nonspecifically disrupt bacterial membranes. To deeply understand the molecular-level detail of the antimicrobial mechanism, here, we artificially established comparative experimental models to investigate the interfacial interaction process between Aur and negatively charged model cell membranes via sum frequency generation vibrational spectroscopy. Sequencing the vibrational signals of phenyl, C–H, and amide groups from Aur has characteristically helped us differentiate between the initial adsorption and subsequent insertion steps upon mutual interaction between Aur and the charged lipids. The phenyl group at the terminal phenylalanine residue can act as an anchor in the adsorption process. The time-dependent signal intensity of α-helices showed a sharp rise once the Aur molecules came into contact with the negatively charged lipids, indicating that the adsorption process was ongoing. Insertion of Aur into the charged lipids then offered the detectable interfacial C–H signals from Aur. The achiral and chiral amide I signals suggest that Aur had formed β-folding-like aggregates after interacting with the charged lipids, along with the subsequent descending α-helical amide I signals. The above-mentioned experimental results provide the molecular-level detail on how the Aur molecules interact with the cell membranes, and such a mechanism study can offer the necessary support for the AMP design and later application.
研究领域:
生物物理学
·
分子生物学
·
微生物学
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产品关联
DOI
PubMed
高影响因子
FOOD HYDROCOLLOIDS
·
2023
·
IF 10.7
Zongyun Yang,Zhen Li,Chu Wang,Peng Wang,Xiaolin Lu,Xinglian Xu
To disclose the interfacial behavior of proteins, in situ and in real-time degree information to which proteins maintain their original conformation at hydrophobic interfaces is critical. Based on energy landscapes theory, surface hydrophobicity and conformation flexibility in control (native) and pale, soft, and exudative-like (PSE-like (pre-denatured)) myosin at the hydrophobic interface was investigated. When the myosin concentration was lower than the keypoint concentration (Control: 0.05 mg/mL, PSE: 0.1 mg/mL), increasing myosin concentration improved the interfacial diffusion rate ( K diff ) and penetration rate ( K p ) at the oil/water interface. Although PSE myosin was easily adsorbed at the interface due to high surface hydrophobicity, hydrophobic aggregation and poor conformation flexibility led to low K diff and rearrangement rate ( K r ), respectively. According to the sum frequency generation (SFG) results, the proportion of the lost α-helix structures in PSE myosin (from 18.93% to 16.79%) was lower than that in control myosin (from 86.64% to 74.18%) after 3 h at the lipid/water surface in situ and in real-time. The difference in interfacial behaviors between control and PSE myosin may be rely on energy barriers from metastable PSE myosin and different unfolding pathways on energy landscapes between two proteins, supported by SFG. Macroscopically, confocal laser scanning microscopy and backscattering (BS) profiles results showed that unstable PSE myosin-soybean oil emulsion with poor interfacial behavior had a larger droplet size and a higher negative peak of ΔBS than control emulsion, respectively. These results have crucial implications for the regulation of interfacial behavior and emulsion characteristics in proteins with varied denatured states.
研究领域:
食品科学
·
生物物理学
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产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2023
·
IF 3.7
XiaoLin Liu,YinYi Ma,QianTong Song,Hao Huang,YuHan He,ShiGang Sun,ZhaoHui Wang
Interface-specific detection of adsorbed key intermediates and product species on the Cu electrode is critical for unraveling the electrocatalytic mechanism of CO2 reduction. In this study, Cu-catalyzed electrocatalysis of CO and CO2 reduction (COR and CO2R, respectively) is investigated using in situ broad-band sum-frequency generation (BB-SFG) spectroscopy. By analysis of the potential-dependent SFG spectra of surface-bound CO (*CO) and possible intermediates in the C–H stretching vibrational range, valuable insights into the electrocatalysis of CO2R are obtained. The SFG spectra of the C–H vibrations reveal two distinct adsorption configurations of surface-bound ethoxy (“standing” and “lying”) on Cu, which provides new molecular evidence to support the presence of C2 intermediates with the atoms of O and C at both ends attached to the Cu surface in the pathway leading to ethanol formation. Moreover, we observed distinct potential-dependent SFG features of *CO in COR and CO2R, while the ethoxy intermediates and product distributions are nearly identical, suggesting that the dimerization of *CO might not be the rate-determining step for the C–C coupling to form ethanol. With these findings, we present a mechanistic scheme for the formation of C1 and C2 products with surface-bound CO and ethoxy intermediates for the formation of ethanol.
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DOI
高影响因子
ELECTROANALYSIS
·
2025
·Vol. 37
·期 7
·e70025
·
IF 2.3
Xiao-Lin Liu,Hao Huang,Heng-Yan Zheng,Yu-Han He,Zhao-Hui Wang
A compact and enclosed optically transparent spectroelectrochemical flow cell was designed specifically for in situ sum frequency generation (SFG) measurements at the charged solid/liquid interface. This thin-layer analysis cell allows the measurement of films on reflective metallic surfaces through a micrometer layer of solution. The cyclic voltammetry and SFG spectrum from an Au working electrode were used to demonstrate the electrochemical and spectroscopic capabilities of the cell. The potential dependent structural changes of the Au electrode and surface molecules were tested to prove the feasibility of the cell for in situ spectroscopy of the electrode processes. The development of this compact spectroelectrochemical flow cell would facilitate future operando studies employing SFG measurements at solid/liquid interfaces.
研究领域:
电化学
·
光谱学
·
材料科学
·
表面科学
·
分析化学
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产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2022
·
IF 6.888
Yongsheng Luo,Ai-Ping Pang,Peizhi Zhu,Dayang Wang,Xiaolin Lu
Revealing interfacial shear-induced structural responsiveness has long been an important topic in that most fluids in nature and human life are in motion and cause interesting boundary phenomena. It is amazing how the polymer chain conformation or local structural features at a boundary change under the effective shear condition. In this study, microfluidic-assisted sum frequency generation (SFG) vibrational spectroscopy and all-atom molecular dynamics (MD) simulation are combined to reveal that the shear flow can effectively block the so-called thermal coil-to-globule transition of the poly(N-isopropylacrylamide) (PNIPAM) brushes on the solid substrate, and the normal coil-to-globule transition transfers to a coil-to-stretch one under shear flow with increasing ambient temperature. Such findings are attributed to the balance between the shear flow and the molecular interaction with respect to the polymer chains and adjacent water molecules, thus demonstrating the significant effect of the shear flow on the structural and dynamic behaviors of the polymer chains at the boundaries from the molecular level.
研究领域:
高分子科学
·
软物质物理
·
表面与界面科学
·
光谱学
·
流体力学
·
分子模拟
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DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2024
·
IF 6.5
Jiangyan Liu,Kaifeng Chen,Yu Zhang,Lizhen Zhou,Fuli Wang,Xueyun Xiang,Hang Wu
This study investigates the interlayer bonding mechanism between epoxy primers and polyurethane topcoats commonly used in marine coatings. Previous studies have focused on the physical bonding between the coatings, but this study focused on the theory of chemical bonding. Using E-44 and HP2000 as primers and MDI toluene solution to simulate a polyurethane topcoat, the changes in the molecular structure at the interface between the epoxy primer and the polyurethane topcoat after curing were revealed by sum-frequency vibrational spectroscopy (SFG) technique. The experiments showed that the hydroxyl (-OH) signals on the surface of the epoxy primer disappeared after contacting with the MDI solution, and the isocyanate (-NCO) and carbonyl (C=O) signals on the urethane topcoat were revealed, suggesting that a chemical reaction occurred between them. The results of SFG analysis were further supported by X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy and scanning electron microscopy. It was found that chemical bonding had a positive effect on the macroscopic properties of the coatings, indicating that the interlayer bonding between the primer and the topcoat could be significantly enhanced by chemical bonding, which provides new theoretical support for the interlayer bonding of the coating support system for marine environment.
研究领域:
材料科学
·
化学工程
·
表面化学
·
海洋技术
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2021
·
IF 5.985
Yongsheng Luo,Chu Wang,Ai-Ping Pang,Xiang Zhang,Dayang Wang,Xiaolin Lu
The interfacial molecular structures of polyelectrolyte brushes grafted on solid substrates are generally influenced by the electrostatic interaction and osmotic pressure. Although the hydrated structures of the strong polyelectrolyte brushes are considered less sensitive to salts present in the surrounding environment at low concentrations, the salts may still influence the distribution of polyelectrolyte counterions and interfacial network structures of water molecules nearby, thereby being correlated to the dissociation of the polyelectrolyte chain segments bound on solid substrates and the entire chain conformation. In this study, sum-frequency generation (SFG) vibrational spectroscopy and coarse-grained molecular dynamics (MD) simulation are combined to investigate the interfacial molecular structures of a strong polyelectrolyte, polystyrene sulfonate (PSS), grafted on silica substrates. The dynamic responses of the OH stretching signals of the interfacial water for the PSS brushes in low-concentration salt solutions bearing monovalent (Na+ and K+), divalent (Ca2+), and trivalent (Y3+) cations are monitored via a connected SFG/microfluidic chip system. First, the salts enhanced the ordering of interfacial water structures irrespective of the nature of cations, reflecting the enlarged electric potential owing to the diffusion of ions and the dissociation of the PSS segments near the solid substrate. Second, the dynamics to reach the final interfacial structural equilibrium appears to be dependent on the type of cations, showing a two-step process and thus presenting evidence for the initial ion diffusion and subsequent dissociation of the chain segments near the substrate wall. Meanwhile, it was found that divalent and trivalent cations caused electrostatic bridging among the polyelectrolyte brush segments, leading to a more disordered chain conformation. We therefore believe that this report provides a fundamental understanding of the interfacial structural and structural transition features with respect to the polyelectrolyte brushes at the molecular level.
研究领域:
材料科学
·
表面化学
·
物理化学
·
高分子科学
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2025
·
IF 9
Tianmeng Zhang,Zhongyang Huang,Dengshuo Cui,Zicheng Luo,Xiuping Zhuo,Yanfeng Liu,Xiuyan Wang,Kai Wu,Jianfeng Zhang,Guibin Li,Shumei Sun,Han Zuilhof,Hao Lu
Two-dimensional (2D) lamellar membranes hold immense promise for sustainable separation technologies, yet their inherent dense interlayer architecture compromises permeability and selectivity. Herein, we propose a defect engineering strategy to construct hierarchical nanofluidic channels within graphene oxide (GO) membranes, by using intercalating polypyrrole (PPy) nanosheets with in-plane nanopores. The synergistic assembly of GO and PPy nanosheets enables tuning of both interlayer spacing and intra-plane nanopores, thereby generating multiscale transport pathways. The optimized PPy/GO membrane achieves a trade-off between selectivity and permeability: >96 % rejection for Congo red, <15 % rejection for salts (NaCl, Na 2 SO 4 , CaCl 2 ), and a remarkable water flux of 310 L m −2 h −1 bar −1 — 5-fold higher than state-of-the-art 2D membranes. Interface selective sum frequency generation (SFG) spectroscopy results reveal that PPy intercalation greatly enhances the order of hydrogen-bonded water at the membrane-water interface, which correlates with the fast and selective separation of dye and salt. Molecular dynamics and hydrodynamic simulations consolidate that the hierarchical channels enhance water permeation via defect-pore sieving, while selectively block organic dyes through size exclusion. Our work not only disentangles the intricate role of defect engineering in tailoring organic/salt separation for 2D membranes, but also provides a scalable approach for advanced separation systems in hypersaline wastewater treatment and resource recovery.
研究领域:
膜科学
·
纳米技术
·
分离技术
·
材料科学
·
环境工程
·
物理化学
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产品关联
DOI
高影响因子
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