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You X, Zhang D, Zhang XG, Li X, Tian JH, Wang YH, Li JF. Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy. Nanomicro Lett 2023; 16:53. [PMID: 38108934 PMCID: PMC10728385 DOI: 10.1007/s40820-023-01285-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 11/09/2023] [Indexed: 12/19/2023]
Abstract
Interfacial water molecules are the most important participants in the hydrogen evolution reaction (HER). Hence, understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism. Unfortunately, investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment. Here, the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry, in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques. Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction. When comparing the different cation electrolyte systems at a given potential, the frequency of the interfacial water peak increases in the specified order: Li+ < Na+ < K+ < Ca2+ < Sr2+. The structure of interfacial water was optimized by adjusting the radius, valence, and concentration of cation to form the two-H down structure. This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance. Therefore, local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.
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Affiliation(s)
- Xueqiu You
- School of Ocean Information Engineering, Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent Processing, Jimei University, Xiamen, 361021, People's Republic of China
| | - Dongao Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, iChEM, College of Chemistry and Chemical Engineering, College of Materials, College of Energy, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Xia-Guang Zhang
- Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, College of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, People's Republic of China
| | - Xiangyu Li
- School of Ocean Information Engineering, Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent Processing, Jimei University, Xiamen, 361021, People's Republic of China
| | - Jing-Hua Tian
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, 361005, People's Republic of China
| | - Yao-Hui Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, iChEM, College of Chemistry and Chemical Engineering, College of Materials, College of Energy, Xiamen University, Xiamen, 361005, People's Republic of China.
| | - Jian-Feng Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, iChEM, College of Chemistry and Chemical Engineering, College of Materials, College of Energy, Xiamen University, Xiamen, 361005, People's Republic of China.
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, 361005, People's Republic of China.
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2
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Irons TJP, Huynh BC, Teale AM, De Proft F, Geerlings P. Molecular charge distributions in strong magnetic fields: a conceptual and current DFT study. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2145245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Tom J. P. Irons
- School of Chemistry, University of Nottingham, Nottingham, UK
| | - Bang C. Huynh
- School of Chemistry, University of Nottingham, Nottingham, UK
| | - Andrew M. Teale
- School of Chemistry, University of Nottingham, Nottingham, UK
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, Oslo, Norway
| | - Frank De Proft
- Research Group of General Chemistry (ALGC), Vrije Universiteit Brussel, Brussels, Belgium
| | - Paul Geerlings
- Research Group of General Chemistry (ALGC), Vrije Universiteit Brussel, Brussels, Belgium
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3
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Wu H, Ghaani MR, Nandi PK, English NJ. Investigation of Dipolar Response of the Hydrated Hen-Egg White Lysozyme Complex under Externally Applied Electric Fields: Insights from Non-equilibrium Molecular Dynamics. J Phys Chem B 2022; 126:858-868. [PMID: 35060735 PMCID: PMC8819654 DOI: 10.1021/acs.jpcb.1c07096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- HaoLun Wu
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Mohammad Reza Ghaani
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Prithwish K. Nandi
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
- Irish Centre for High-End Computing, Trinity Enterprise Centre, Pearse Street, Dublin 2, Ireland
| | - Niall J. English
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
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Müller WA, Sarkis JR, Marczak LDF, Muniz AR. Molecular dynamics study of the effects of static and oscillating electric fields in ovalbumin. INNOV FOOD SCI EMERG 2022. [DOI: 10.1016/j.ifset.2021.102911] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Marracino P, Caramazza L, Montagna M, Ghahri R, D'Abramo M, Liberti M, Apollonio F. Electric-driven membrane poration: A rationale for water role in the kinetics of pore formation. Bioelectrochemistry 2021; 143:107987. [PMID: 34794113 DOI: 10.1016/j.bioelechem.2021.107987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 11/26/2022]
Abstract
Electroporation is a well-established technique used to stimulate cells, enhancing membrane permeability by inducing reversible membrane pores. In the absence of experimental observation of the dynamics of pore creation, molecular dynamics studies provide the molecular-level evidence that the electric field promotes pore formation. Although single steps in the pore formation process are well assessed, a kinetic model representing the mathematical description of the electroporation process, is lacking. In the present work we studied the basis of the pore formation process, providing a rationale for the definition of a first-order kinetic scheme. Here, authors propose a three-state kinetic model for the process based on the assessed mechanism of water defects intruding at the water/lipid interface, when applying electric field intensities at the edge of the linear regime. The methodology proposed is based on the use of two robust biophysical quantities analyzed for the water molecules intruding at the water/lipid interface: (i) number of hydrogen bonds; (ii) number of contacts. The final model, sustained by a robust statistical sampling, provides kinetic constants for the transitions from the intact bilayer state to the hydrophobic pore state.
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Affiliation(s)
- Paolo Marracino
- Rise Technology S.r.l., L.re Paolo Toscanelli 170, 00121 Rome, Italy
| | - Laura Caramazza
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Maria Montagna
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Department of Chemistry, Sapienza Sapienza University of Rome, Rome, Italy
| | - Ramin Ghahri
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy
| | - Marco D'Abramo
- Department of Chemistry, Sapienza Sapienza University of Rome, Rome, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy.
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Elgabarty H, Kaliannan NK, Kühne TD. Enhancement of the local asymmetry in the hydrogen bond network of liquid water by an ultrafast electric field pulse. Sci Rep 2019; 9:10002. [PMID: 31292493 PMCID: PMC6620291 DOI: 10.1038/s41598-019-46449-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 06/27/2019] [Indexed: 11/18/2022] Open
Abstract
Condensed phase electron decomposition analysis based on density functional theory has recently revealed an asymmetry in the hydrogen-bond network in liquid water, in the sense that a significant population of water molecules are simultaneously donating and accepting one strong hydrogen-bond and another substantially weaker one. Here we investigate this asymmetry, as well as broader structural and energetic features of water's hydrogen-bond network, following the application of an intense electric field square pulse that invokes the ultrafast reorientation of water molecules. We find that the necessary field-strength required to invoke an ultrafast alignment in a picosecond time window is on the order of 108 Vm-1. The resulting orientational anisotropy imposes an experimentally measurable signature on the structure and dynamics of the hydrogen-bond network, including its asymmetry, which is strongly enhanced. The dependence of the molecular reorientation dynamics on the field-strength can be understood by relating the magnitude of the water dipole-field interaction to the rotational kinetic energy, as well as the hydrogen-bond energy.
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Affiliation(s)
- Hossam Elgabarty
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany
| | - Naveen Kumar Kaliannan
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany
| | - Thomas D Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany.
- Paderborn Center for Parallel Computing and Institute for Lightweight Design, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany.
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Affiliation(s)
- Mahdi Shafiei
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
| | - Michael von Domaros
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, USA
| | - Dusan Bratko
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
| | - Alenka Luzar
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
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Abstract
The reductive tricarboxylic acid (rTCA) cycle is among the most plausible candidates for the first autotrophic metabolism in the earliest life. Extant enzymes fixing CO2 in this cycle contain cofactors at the catalytic centers, but it is unlikely that the protein/cofactor system emerged at once in a prebiotic process. Here, we discuss the feasibility of non-enzymatic cofactor-assisted drive of the rTCA reactions in the primitive Earth environments, particularly focusing on the acetyl-CoA conversion to pyruvate. Based on the energetic and mechanistic aspects of this reaction, we propose that the deep-sea hydrothermal vent environments with active electricity generation in the presence of various sulfide catalysts are a promising setting for it to progress. Our view supports the theory of an autotrophic origin of life from primordial carbon assimilation within a sulfide-rich hydrothermal vent.
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Floros S, Liakopoulou-Kyriakides M, Karatasos K, Papadopoulos GE. Frequency Dependent Non- Thermal Effects of Oscillating Electric Fields in the Microwave Region on the Properties of a Solvated Lysozyme System: A Molecular Dynamics Study. PLoS One 2017; 12:e0169505. [PMID: 28129348 PMCID: PMC5271316 DOI: 10.1371/journal.pone.0169505] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 12/19/2016] [Indexed: 11/19/2022] Open
Abstract
The use of microwaves in every day's applications raises issues regarding the non thermal biological effects of microwaves. In this work we employ molecular dynamics simulations to advance further the dielectric studies of protein solutions in the case of lysozyme, taking into consideration possible frequency dependent changes in the structural and dynamic properties of the system upon application of electric field in the microwave region. The obtained dielectric spectra are identical with those derived in our previous work using the Fröhlich-Kirkwood approach in the framework of the linear response theory. Noticeable structural changes in the protein have been observed only at frequencies near its absorption maximum. Concerning Cα position fluctuations, different frequencies affected different regions of the protein sequence. Furthermore, the influence of the field on the kinetics of protein-water as well as on the water-water hydrogen bonds in the first hydration shell has been studied; an extension of the Luzar-Chandler kinetic model was deemed necessary for a better fit of the applied field results and for the estimation of more accurate hydrogen bond lifetime values.
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Affiliation(s)
- Stelios Floros
- Faculty of Chemical Engineering, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Maria Liakopoulou-Kyriakides
- Faculty of Chemical Engineering, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Kostas Karatasos
- Faculty of Chemical Engineering, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Georgios E. Papadopoulos
- Faculty of Health Sciences, Department of Biochemistry and Biotechnology, University of Thessaly, Mezourlo, Larisa, Greece
- * E-mail:
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Luis D, López-Lemus J, Maspoch ML, Franco-Urquiza E, Saint-Martin H. Methane hydrate: shifting the coexistence temperature to higher temperatures with an external electric field. Molecular Simulation 2016. [DOI: 10.1080/08927022.2016.1139704] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- D.P. Luis
- CONACYT Research Fellow-Centro de Ingeniería y Desarrollo Industrial, Querétaro, México
| | - J. López-Lemus
- Facultad de ciencias, Universidad Autónoma del Estado de México, Toluca, México
| | - M. Ll. Maspoch
- Centre Català del Plàstic, Universitat Politècnica de Catalunya, Terrassa, Spain
| | - E.A. Franco-Urquiza
- CONACYT Research Fellow-Centro de Ingeniería y Desarrollo Industrial, Querétaro, México
| | - H. Saint-Martin
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México,
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11
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Xu Z, Wang C, Sheng N, Hu G, Zhou Z, Fang H. Manipulation of a neutral and nonpolar nanoparticle in water using a nonuniform electric field. J Chem Phys 2016; 144:014302. [PMID: 26747801 DOI: 10.1063/1.4939151] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The manipulation of nanoparticles in water is of essential importance in chemical physics, nanotechnology, medical technology, and biotechnology applications. Generally, a particle with net charges or charge polarity can be driven by an electric field. However, many practical particles only have weak and even negligible charge and polarity, which hinders the electric field to exert a force large enough to drive these nanoparticles directly. Here, we use molecular dynamics simulations to show that a neutral and nonpolar nanoparticle in liquid water can be driven directionally by an external electric field. The directed motion benefits from a nonuniform water environment produced by a nonuniform external electric field, since lower water energies exist under a higher intensity electric field. The nanoparticle spontaneously moves toward locations with a weaker electric field intensity to minimize the energy of the whole system. Considering that the distance between adjacent regions of nonuniform field intensity can reach the micrometer scale, this finding provides a new mechanism of manipulating nanoparticles from the nanoscale to the microscale.
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Affiliation(s)
- Zhen Xu
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Chunlei Wang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Nan Sheng
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Guohui Hu
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China
| | - Zhewei Zhou
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China
| | - Haiping Fang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
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12
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Luis DP, Herrera-Hernández EC, Saint-Martin H. A theoretical study of the dissociation of the sI methane hydrate induced by an external electric field. J Chem Phys 2015; 143:204503. [PMID: 26627964 DOI: 10.1063/1.4936214] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular dynamics simulations in the equilibrium isobaric-isothermal (NPT) ensemble were used to examine the strength of an external electric field required to dissociate the methane hydrate sI structure. The water molecules were modeled using the four-site TIP4P/Ice analytical potential and methane was described as a simple Lennard-Jones interaction site. A series of simulations were performed at T = 260 K with P = 80 bars and at T = 285 K with P = 400 bars with an applied electric field ranging from 1.0 V nm(-1) to 5.0 V nm(-1). For both (T,P) conditions, applying a field greater than 1.5 V nm(-1) resulted in the orientation of the water molecules such that an ice Ih-type structure was formed, from which the methane was segregated. When the simulations were continued without the external field, the ice-like structures became disordered, resulting in two separate phases: gas methane and liquid water.
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Affiliation(s)
- D P Luis
- CONACYT Research Fellow-Centro de Ingeniería y Desarrollo Industrial, Av. Playa Pie de la Cuesta No. 702, Desarrollo San Pablo, Querétaro, Querétaro 76125, Mexico
| | - E C Herrera-Hernández
- CONACYT Research Fellow-Centro de Ingeniería y Desarrollo Industrial, Av. Playa Pie de la Cuesta No. 702, Desarrollo San Pablo, Querétaro, Querétaro 76125, Mexico
| | - H Saint-Martin
- Instituto de Ciencias Físicas, Universidad Autónoma de México, Apartado Postal 48-3, Cuernavaca, Morelos 62251, Mexico
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He J, Noto VD, Paddison SJ. The structure of water–methanol mixtures under an electric field: Ab initio molecular dynamics simulations. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.06.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Marracino P, Liberti M, d'Inzeo G, Apollonio F. Water response to intense electric fields: A molecular dynamics study. Bioelectromagnetics 2015; 36:377-85. [PMID: 25877041 DOI: 10.1002/bem.21916] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 03/11/2015] [Indexed: 02/04/2023]
Abstract
This paper investigated polarization properties of water molecules in close proximity to an ionic charge in the presence of external electric fields by using an approach based on simulations at the atomic level. We chose sodium and chloride ions in water as examples of dilute ionic solutions and used molecular dynamics simulations to systematically investigate the influence of an external static electric field on structural, dipolar, and polarization properties of water near charged ions. Results showed that a threshold electric field higher than 10(8) V/m is needed to affect water polarization and increase mean dipole moment of water molecules close to the ion. A similar threshold holds for water permittivity profiles, although a field 10× higher is needed to ensure that water permittivity is almost constant independently of the position close to the ion. Electric fields of such intensities can greatly enhance polarizability of water in hydration shells around ions.
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Affiliation(s)
- Paolo Marracino
- Department of Information Engineering, Electronics and Telecommunications (DIET), Italian Inter-University Center of Electromagnetic Fields and Biosystems (ICEmB), "La Sapienza" University of Rome, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications (DIET), Italian Inter-University Center of Electromagnetic Fields and Biosystems (ICEmB), "La Sapienza" University of Rome, Italy
| | - Guglielmo d'Inzeo
- Department of Information Engineering, Electronics and Telecommunications (DIET), Italian Inter-University Center of Electromagnetic Fields and Biosystems (ICEmB), "La Sapienza" University of Rome, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications (DIET), Italian Inter-University Center of Electromagnetic Fields and Biosystems (ICEmB), "La Sapienza" University of Rome, Italy
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Beyer C, Christen P, Jelesarov I, Fröhlich J. Real-time assessment of possible electromagnetic-field-induced changes in protein conformation and thermal stability. Bioelectromagnetics 2014; 35:470-8. [PMID: 25123495 DOI: 10.1002/bem.21865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 06/12/2014] [Indexed: 01/20/2023]
Abstract
Previous studies on possible interactions of radiofrequency electromagnetic fields (RF EMFs) with proteins have suggested that RF EMFs might affect protein structure and folding kinetics. In this study, the isolated thermosensor protein GrpE of the Hsp70 chaperone system of Escherichia coli was exposed to EMFs of various frequencies and field strengths under strictly controlled conditions. Circular dichroism spectroscopy was used to monitor possible structural changes. Simultaneously, temperature was recorded at each point of observation. The coiled-coil part of GrpE has been reported to undergo a well-defined and fully reversible folding/unfolding transition, thus facilitating the differentiation between thermal and non-thermal effects of RF EMFs. Any direct effect of EMF on the conformation and/or stability would result in a shift of the conformational equilibrium of the protein at a given temperature. Possible immediate (t ≤ 0.1 s) and delayed (t ≥ 30 s) effects of RF EMFs were investigated with sinusoidal signals of 0.1, 1.0, and 1.9 GHz at various field strengths up to 5.0 kV/m and with GSM signals at 0.3 kV/m in the protein solution. Taking the overall uncertainty of the experimental system into account, possible RF EMF-induced shifts in the conformational equilibrium of less than 1% of its total range might have been detected. The results obtained with the different experimental protocols indicate, however, that the conformational equilibrium of GrpE is insensitive to electromagnetic fields in the tested range of frequency and field strength.
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Affiliation(s)
- Christian Beyer
- Laboratory for Electromagnetics Fields and Microwave Electronics (IFH), ETH Zurich, Zurich, Switzerland
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16
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Marshall BD, Chapman WG, Telo da Gama MM. Classical density functional theory for associating fluids in orienting external fields. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 88:060301. [PMID: 24483368 DOI: 10.1103/physreve.88.060301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Indexed: 06/03/2023]
Abstract
We develop a classical density functional theory (DFT) for two-site associating fluids in spatially homogeneous external fields which exhibit orientational inhomogeneities. The Helmholtz free-energy functional is obtained using Wertheim's thermodynamic perturbation theory and the orientational distribution function is obtained using DFT in the canonical ensemble. It is shown that an orientating field significantly enhances association by ordering the molecules, thereby reducing the entropic penalty of association. It is also shown that association enhances the orientational order for fixed field strength.
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Affiliation(s)
- Bennett D Marshall
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 South Main Street, Houston, Texas 77005, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 South Main Street, Houston, Texas 77005, USA
| | - Margarida M Telo da Gama
- Centro de Física Teórica e Computacional, Avenida Professor Gama Pinto 2, P-1649-003 Lisbon, Portugal and Departamento de Física, Faculdade de Ciências da Universidade de Lisboa, P-1749-016 Lisbon, Portugal
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Zhao Y, Dong K, Liu X, Zhang S, Zhu J, Wang J. Structure of ionic liquids under external electric field: a molecular dynamics simulation. Molecular Simulation 2012. [DOI: 10.1080/08927022.2011.610894] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Daub CD, Bratko D, Luzar A. Nanoscale Wetting Under Electric Field from Molecular Simulations. Multiscale Molecular Methods in Applied Chemistry 2011; 307:155-79. [DOI: 10.1007/128_2011_188] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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22
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Maerzke KA, Siepmann JI. Effects of an Applied Electric Field on the Vapor−Liquid Equilibria of Water, Methanol, and Dimethyl Ether. J Phys Chem B 2010; 114:4261-70. [DOI: 10.1021/jp9101477] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katie A. Maerzke
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
| | - J. Ilja Siepmann
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
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Affiliation(s)
- Zixue Su
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, U.K
| | - Michael Bühl
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, U.K
| | - Wuzong Zhou
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, U.K
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Boily JF. Elucidation of oxyanion coordination geometries at solid surfaces of varied electric field strengths. Phys Chem Chem Phys 2009; 11:8133-5. [DOI: 10.1039/b909925e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Calvo F, Dugourd P. Folding of gas-phase polyalanines in a static electric field: alignment, deformations, and polarization effects. Biophys J 2008; 95:18-32. [PMID: 18223004 PMCID: PMC2426642 DOI: 10.1529/biophysj.107.124685] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 12/28/2007] [Indexed: 11/18/2022] Open
Abstract
Monte Carlo simulations of the temperature-induced unfolding of small gas-phase polyalanines in a static, homogeneous electric field are reported, based on the AMBER ff96 force field. The peptides exhibit a structural transition from the native alpha-helix state to entropically favored beta-sheet conformations, before eventually turning to extended coil at higher temperatures. Upon switching the electric field, the molecules undergo preferential alignment of their dipole moment vector toward the field axis and a shift of the alpha-beta transition to higher temperatures. At higher field strengths (>10(8) V/m) the molecules stretch and the alpha-beta and beta-coil transitions merge. A simple three-state model is shown to account for the observed behavior. Under even higher fields, density functional theory calculations and a polarizable force field both show that electronic rearrangements tend to further increase the dipole moment, polarization effects being approximately half in magnitude with respect to stretching effect. Finally a tentative (temperature, field-strength) phase diagram is sketched.
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Affiliation(s)
- F Calvo
- Centre National de la Recherche Scientifique, Laboratoire de Spectrometrie Ionique et Moleculaire, Université de Lyon, Université Lyon 1, Villeurbanne, France.
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Cramer T, Zerbetto F, García R. Molecular mechanism of water bridge buildup: field-induced formation of nanoscale menisci. Langmuir 2008; 24:6116-20. [PMID: 18484756 DOI: 10.1021/la800220r] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We perform molecular dynamics calculations to describe, at the molecular level, the formation of a water bridge induced by an electric field. Restriction of orientational degrees of freedom (confinement) of water dipoles at the interfaces leads to a polarizability that depends on the shape of the water system, that is, droplet versus pillar. Above a threshold field of 1.2 V nm(-1), the competition between orientational confinement and electric field leads to the sudden formation of a water pillar. The formation of a water bridge is marked by a first order discontinuity in the total energy of the system. The simulations offer a molecular explanation for the threshold voltage and hysteresis behavior observed in the formation of nanoscale liquid bridges with a force microscope.
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Affiliation(s)
- Tobias Cramer
- Dipartimento di Chimica G. Ciamician, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy.
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Abstract
The understanding of the hydrogen (H) bonded structure of water near charged surfaces is highly relevant in the context of several important areas of research, including electrochemistry, biochemistry, and geology. Past simulation studies have not yielded conclusive answers; while some suggest breakage of H bonds near a charged surface, others argue that H-bonding interactions can stabilize the structure of surface water even in the presence of high electric (E) fields. Recent experiments, on the other hand, suggest a partial breakdown of H-bond structure near a charged electrode. In all these studies, however, the conclusions regarding H bonding were drawn based on the density profile of hydrogen/oxygen atoms near the interface. In the present paper, we investigate this problem using a new theory that explicitly accounts for the influence of E field on the H-bond network of water near the solid-liquid interface. We find that the average number of H bonds per molecule in bulk increases from approximately 3.8 at E<10(5) V/m to approximately 3.95 at E=2x10(9) V/m (suggesting enhancement in H-bond network), while that near the electrode surface decreases from approximately 2.8 to a saturation value of approximately 2.0 (suggesting weakening of H-bond network).
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Affiliation(s)
- S J Suresh
- Unilever Research India, Hindustan Lever Research Centre, 64 Main Road, Whitefield, Bangalore 560066, India.
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Abstract
The understanding of the structure of hydrogen (H) bonding liquids in electric (E) fields is important in the context of several areas of research, such as electrochemistry, surface science, and thermodynamics of electrolyte solutions. We had earlier presented a general thermodynamic framework for this purpose, and had shown that the application of E field enhances H-bond interactions among water molecules. The present investigation with methanol suggests a different result-the H-bond structure, as indicated by the average number of H bonds per molecule, goes through a maxima with increasing field strength. This result is explained based on the symmetry in the location of the H-bonding sites in the two types of molecules.
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Affiliation(s)
- S J Suresh
- Unilever Research India, 64 Main Road, Whitefield, Bangalore 560066, India.
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Abstract
We manifest a significant influence of field direction and polarity on surface wetting, when the latter is tuned by application of an external electric field. Thermodynamics of field-induced filling of hydrocarbon-like nanopores with water is studied by open ensemble molecular simulation. Increased field strength consistently results in water-filling and electrostriction in hydrophobic nanopores. A threshold field commensurate with surface charge density of about one elementary charge per 10 nm2 suffices to render prototypical paraffin surfaces hydrophilic. When a field is applied in the direction perpendicular to the confining walls, the competition between orientational polarization and angle preferences of interfacial water molecules relative to the walls results in an asymmetric wettability of opposing surfaces (Janus interface). Reduction of surface free energy observed upon alignment of confinement walls with field direction suggests a novel mechanism whereby the applied electric field can operate selectively on water-filled nanotubes while empty ones remain unaffected.
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Affiliation(s)
- Dusan Bratko
- Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284-2006, USA.
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Abstract
The behavior of small water clusters, (H2O)n, n=2-5 and n=8, in a uniform electric field is investigated for three related rigid-body models. Changes in the properties of the low-lying potential energy minima and the rearrangement pathways between them are examined. Results for certain structural transitions are compared with recent ab initio calculations. The models are found to give qualitatively similar trends, and there is some evidence that as the applied field strength is increased the quantitative differences between the models are also reduced.
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Affiliation(s)
- Tim James
- University Chemical Laboratories, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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Abstract
Water molecules in clefts and small clusters are in a significantly different environment than in bulk water. We have carried out ab initio calculations that demonstrate this in a series of clusters, showing that cooperative effects must be taken into account in the treatment of hydrogen bonds and water clusters in such bounded systems. Hydrogen bonds between water molecules in simulations are treated most frequently by using point charge water potentials, such as TIP3P or SPC, sometimes with a polarizable extension. These produce excellent results in bulk water, for which they are calibrated. Clefts are different from bulk; it is necessary to look at smaller systems, and investigate the effect of limited numbers of neighbors. We start with a study of isolated clusters of water with varying numbers of neighbors of a hydrogen bonded pair of water molecules. The cluster as a whole is in vacuum. The clusters are defined so as to provide the possible arrangements of nearest neighbors of a central hydrogen bonded pair of water molecules. We then scan the length and angles of the central hydrogen bond of the clusters, using density functional theory, for each possible arrangement of donor and acceptor hydrogen bonds on the central hydrogen bonding pair; the potential of interaction of two water molecules varies with the number of donor and of acceptor neighbors. This also involves changes in charge on the water molecules as a function of bond length, and changes in energy and length as a function of number of neighboring donor and acceptor molecules. Energy varies by approximately 6 k(B)T near room temperature from the highest to the lowest energy when bond length alone is varied, enough to seriously affect simulations.
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Affiliation(s)
- Vasiliy S Znamenskiy
- Department of Chemistry, City College of the City University of New York, 138 St and Convent Ave, New York NY 10031
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Abstract
In this work we study a tridimensional statistical model for the hydrogen-bond (HB) network formed in liquid water in the presence of an external electric field. This model is analogous to the so-called square water, whose ground state gives a good estimate for the residual entropy of the ice. In our case, each water molecule occupies one site of a cubic lattice, and no hole is allowed. The hydrogen atoms of water molecules are disposed at the lines connecting nearest-neighbor sites, in a way that each water can be found in 15 different states. We say that there is a hydrogen bond between two neighboring molecules when only one hydrogen is in the line connecting both molecules. Through Monte Carlo simulations with Metropolis and entropic sampling algorithms, and by exact calculations for small lattices, we determined the dependence of the number of molecules aligned to the field and the number of hydrogen bonds per molecule as a function of temperature and the intensity of the external field. The results for both approaches showed that, different of the two-dimensional case, there is no maximum in the number of HBs as a function of the electric field. However, we observed nonmonotonic behaviors as a function of the temperature of the quantities of interest. We also found the dependence of the entropy on the external electric field at very low temperatures. In this case, the entropy vanishes for the value of the external field for which the contributions to the total energy coming from the HBs and the field become the same.
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Affiliation(s)
- M Girardi
- Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970 São Paulo, São Paulo, Brazil.
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