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Krishnamurthi V, Vaillant PHA, Mata J, Nguyen CK, Parker CJ, Zuraiqi K, Bryant G, Chiang K, Russo SP, Christofferson AJ, Elbourne A, Daeneke T. Structural Evolution of Liquid Metals and Alloys. Adv Mater 2024:e2403885. [PMID: 38739417 DOI: 10.1002/adma.202403885] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/02/2024] [Indexed: 05/14/2024]
Abstract
Low-melting liquid metals are emerging as a new group of highly functional solvents due to their capability to dissolve and alloy various metals in their elemental state to form solutions as well as colloidal systems. Furthermore, these liquid metals can facilitate and catalyze multiple unique chemical reactions. Despite the intriguing science behind liquid metals and alloys, very little is known about their fundamental structures in the nanometric regime. To bridge this gap, this work employs small angle neutron scattering and molecular dynamics simulations, revealing that the most commonly used liquid metal solvents, EGaIn and Galinstan, are surprisingly structured with the formation of clusters ranging from 157 to 15.7 Å. Conversely, noneutectic liquid metal alloys of GaSn or GaIn at low solute concentrations of 1, 2, and 5 wt%, as well as pure Ga, do not exhibit these structures. Importantly, the eutectic alloys retain their structure even at elevated temperatures of 60 and 90 °C, highlighting that they are not just simple homogeneous fluids consisting of individual atoms. Understanding the complex soft structure of liquid alloys will assist in comprehending complex phenomena occurring within these fluids and contribute to deriving reaction mechanisms in the realm of synthesis and liquid metal-based catalysis.
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Affiliation(s)
- Vaishnavi Krishnamurthi
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Pierre H A Vaillant
- School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Jitendra Mata
- Australian Centre for Neutron Scattering (ACNS), Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW, 2234, Australia
- School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Chung Kim Nguyen
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Caiden J Parker
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Karma Zuraiqi
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Gary Bryant
- School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Ken Chiang
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Salvy P Russo
- School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - Andrew J Christofferson
- School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - Aaron Elbourne
- School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
| | - Torben Daeneke
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, VIC, 3001, Australia
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Kilbride RC, Spooner ELK, Burg SL, Oliveira BL, Charas A, Bernardo G, Dalgliesh R, King S, Lidzey DG, Jones RAL, Parnell AJ. The Nanoscale Structure and Stability of Organic Photovoltaic Blends Processed with Solvent Additives. Small 2024:e2311109. [PMID: 38597752 DOI: 10.1002/smll.202311109] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/04/2024] [Indexed: 04/11/2024]
Abstract
Controlling the nanomorphology in bulk heterojunction photoactive blends is crucial for optimizing the performance and stability of organic photovoltaic (OPV) technologies. A promising approach is to alter the drying dynamics and consequently, the nanostructure of the blend film using solvent additives such as 1,8-diiodooctane (DIO). Although this approach is demonstrated extensively for OPV systems incorporating fullerene-based acceptors, it is unclear how solvent additive processing influences the morphology and stability of nonfullerene acceptor (NFA) systems. Here, small angle neutron scattering (SANS) is used to probe the nanomorphology of two model OPV systems processed with DIO: a fullerene-based system (PBDB-T:PC71BM) and an NFA-based system (PBDB-T:ITIC). To overcome the low intrinsic neutron scattering length density contrast in polymer:NFA blend films, the synthesis of a deuterated NFA analog (ITIC-d52) is reported. Using SANS, new insights into the nanoscale evolution of fullerene and NFA-based systems are provided by characterizing films immediately after fabrication, after thermal annealing, and after aging for 1 year. It is found that DIO processing influences fullerene and NFA-based systems differently with NFA-based systems characterized by more phase-separated domains. After long-term aging, SANS reveals both systems demonstrate some level of thermodynamic induced domain coarsening.
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Affiliation(s)
- Rachel C Kilbride
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, S3 7HF, United Kingdom
- Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom
| | - Emma L K Spooner
- Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom
- The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PY, United Kingdom
| | - Stephanie L Burg
- Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom
| | - Bárbara L Oliveira
- Instituto de Telecomunicações, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa, P-1049-001, Portugal
| | - Ana Charas
- Instituto de Telecomunicações, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa, P-1049-001, Portugal
| | - Gabriel Bernardo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, 4200-465, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, 4200-465, Portugal
| | - Robert Dalgliesh
- ISIS Neutron and Muon Spallation Source, Rutherford Appleton Laboratories, Oxfordshire, OX11 0QX, United Kingdom
| | - Stephen King
- ISIS Neutron and Muon Spallation Source, Rutherford Appleton Laboratories, Oxfordshire, OX11 0QX, United Kingdom
| | - David G Lidzey
- Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom
| | - Richard A L Jones
- Department of Materials, The University of Manchester, Sackville Street Building, Manchester, M1 3BB, United Kingdom
| | - Andrew J Parnell
- Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom
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Rogozhkin SV, Klauz AV, Ke Y, Almásy L, Nikitin AA, Khomich AA, Bogachev AA, Gorshkova YE, Bokuchava GD, Kopitsa GP, Sun L. Study of Precipitates in Oxide Dispersion-Strengthened Steels by SANS, TEM, and APT. Nanomaterials (Basel) 2024; 14:194. [PMID: 38251158 DOI: 10.3390/nano14020194] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/23/2024]
Abstract
In this work, the nanostructure of oxide dispersion-strengthened steels was studied by small-angle neutron scattering (SANS), transmission electron microscopy (TEM), and atom probe tomography (APT). The steels under study have different alloying systems differing in their contents of Cr, V, Ti, Al, and Zr. The methods of local analysis of TEM and APT revealed a significant number of nanosized oxide particles and clusters. Their sizes, number densities, and compositions were determined. A calculation of hardness from SANS data collected without an external magnetic field, or under a 1.1 T field, showed good agreement with the microhardness of the materials. The importance of taking into account two types of inclusions (oxides and clusters) and both nuclear and magnetic scattering was shown by the analysis of the scattering data.
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Affiliation(s)
- Sergey V Rogozhkin
- Institute of Nuclear Physics and Engineering, National Research Nuclear University "MEPhI", 115409 Moscow, Russia
- National Research Center "Kurchatov Institute", 123182 Moscow, Russia
| | - Artem V Klauz
- Institute of Nuclear Physics and Engineering, National Research Nuclear University "MEPhI", 115409 Moscow, Russia
- National Research Center "Kurchatov Institute", 123182 Moscow, Russia
| | - Yubin Ke
- Spallation Neutron Source Science Center, Dongguan 523803, China
| | - László Almásy
- Institute for Energy Security and Environmental Safety, HUN-REN Centre for Energy Research, 1121 Budapest, Hungary
| | - Alexander A Nikitin
- Institute of Nuclear Physics and Engineering, National Research Nuclear University "MEPhI", 115409 Moscow, Russia
- National Research Center "Kurchatov Institute", 123182 Moscow, Russia
| | - Artem A Khomich
- Institute of Nuclear Physics and Engineering, National Research Nuclear University "MEPhI", 115409 Moscow, Russia
- National Research Center "Kurchatov Institute", 123182 Moscow, Russia
| | - Aleksei A Bogachev
- Institute of Nuclear Physics and Engineering, National Research Nuclear University "MEPhI", 115409 Moscow, Russia
- National Research Center "Kurchatov Institute", 123182 Moscow, Russia
| | - Yulia E Gorshkova
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
- Institute of Physics, Kazan Federal University, 420008 Kazan, Russia
| | | | - Gennadiy P Kopitsa
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 188300 Gatchina, Russia
| | - Liying Sun
- Institute of New Materials, Guangdong Academy of Sciences, Guangzhou 510650, China
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Gao X, Thrush JW, Gor J, Naismith JH, Owens RJ, Perkins SJ. The solution structure of the heavy chain-only C5-Fc nanobody reveals exposed variable regions that are optimal for COVID-19 antigen interactions. J Biol Chem 2023; 299:105337. [PMID: 37838175 PMCID: PMC10682267 DOI: 10.1016/j.jbc.2023.105337] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/28/2023] [Accepted: 10/09/2023] [Indexed: 10/16/2023] Open
Abstract
Heavy chain-only antibodies can offer advantages of higher binding affinities, reduced sizes, and higher stabilities than conventional antibodies. To address the challenge of SARS-CoV-2 coronavirus, a llama-derived single-domain nanobody C5 was developed previously that has high COVID-19 virus neutralization potency. The fusion protein C5-Fc comprises two C5 domains attached to a glycosylated Fc region of a human IgG1 antibody and shows therapeutic efficacy in vivo. Here, we have characterized the solution arrangement of the molecule. Two 1443 Da N-linked glycans seen in the mass spectra of C5-Fc were removed and the glycosylated and deglycosylated structures were evaluated. Reduction of C5-Fc with 2-mercaptoethylamine indicated three interchain Cys-Cys disulfide bridges within the hinge. The X-ray and neutron Guinier RG values, which provide information about structural elongation, were similar at 4.1 to 4.2 nm for glycosylated and deglycosylated C5-Fc. To explain these RG values, atomistic scattering modeling based on Monte Carlo simulations resulted in 72,737 and 56,749 physically realistic trial X-ray and neutron structures, respectively. From these, the top 100 best-fit X-ray and neutron models were identified as representative asymmetric solution structures, similar to that of human IgG1, with good R-factors below 2.00%. Both C5 domains were solvent exposed, consistent with the functional effectiveness of C5-Fc. Greater disorder occurred in the Fc region after deglycosylation. Our results clarify the importance of variable and exposed C5 conformations in the therapeutic function of C5-Fc, while the glycans in the Fc region are key for conformational stability in C5-Fc.
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Affiliation(s)
- Xin Gao
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Joseph W Thrush
- Department of Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, United Kingdom
| | - Jayesh Gor
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - James H Naismith
- Department of Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, United Kingdom
| | - Raymond J Owens
- Department of Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, United Kingdom
| | - Stephen J Perkins
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom.
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Hammond OS, Bousrez G, Mehler F, Li S, Shimpi MR, Doutch J, Cavalcanti L, Glavatskih S, Antzutkin ON, Rutland MW, Mudring AV. Molecular Architecture Effects on Bulk Nanostructure in Bis(Orthoborate) Ionic Liquids. Small 2023; 19:e2300912. [PMID: 37395635 DOI: 10.1002/smll.202300912] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/11/2023] [Indexed: 07/04/2023]
Abstract
A series of 19 ionic liquids (ILs) based on phosphonium and imidazolium cations of varying alkyl-chain lengths with the orthoborate anions bis(oxalato)borate [BOB]- , bis(mandelato)borate, [BMB]- and bis(salicylato)borate, [BScB]- , are synthesized and studied using small-angle neutron scattering (SANS). All measured systems display nanostructuring, with 1-methyl-3-n-alkyl imidazolium-orthoborates forming clearly bicontinuous L3 spongelike phases when the alkyl chains are longer than C6 (hexyl). L3 phases are fitted using the Teubner and Strey model, and diffusely-nanostructured systems are primarily fitted using the Ornstein-Zernicke correlation length model. Strongly-nanostructured systems have a strong dependence on the cation, with molecular architecture variation explored to determine the driving forces for self-assembly. The ability to form well-defined complex phases is effectively extinguished in several ways: methylation of the most acidic imidazolium ring proton, replacing the imidazolium 3-methyl group with a longer hydrocarbon chain, substitution of [BOB]- by [BMB]- , or exchanging the imidazolium for phosphonium systems, irrespective of phosphonium architecture. The results suggest there is only a small window of opportunity, in terms of molecular amphiphilicity and cation:anion volume matching, for the formation of stable extensive bicontinuous domains in pure bulk orthoborate-based ILs. Particularly important for self-assembly processes appear to be the ability to form H-bonding networks, which offer additional versatility in imidazolium systems.
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Affiliation(s)
- Oliver S Hammond
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, SE-114 18, Sweden
- Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C, 8000, Denmark
| | - Guillaume Bousrez
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, SE-114 18, Sweden
- Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C, 8000, Denmark
| | - Filip Mehler
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, SE-100 40, Sweden
| | - Sichao Li
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, SE-100 40, Sweden
| | - Manishkumar R Shimpi
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, SE-114 18, Sweden
- Chemistry of Interfaces, Luleå University of Technology, Luleå, SE-971 87, Sweden
| | - James Doutch
- ISIS Neutron & Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell-Oxford, OX11 0QX, UK
| | - Leide Cavalcanti
- ISIS Neutron & Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell-Oxford, OX11 0QX, UK
| | - Sergei Glavatskih
- Department of Engineering Design, KTH Royal Institute of Technology, Stockholm, SE-10044, Sweden
- School of Chemistry, University of New South Wales, Sydney, 2052, Australia
- Department of Electromechanical, Systems and Metal Engineering, Ghent University, Ghent, B-9052, Belgium
| | - Oleg N Antzutkin
- Chemistry of Interfaces, Luleå University of Technology, Luleå, SE-971 87, Sweden
| | - Mark W Rutland
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, SE-100 40, Sweden
- School of Chemistry, University of New South Wales, Sydney, 2052, Australia
- Bioeconomy and Health Department Materials and Surface Design, RISE Research Institutes of Sweden, Stockholm, SE-114 86, Sweden
- Laboratoire de Tribologie et Dynamique des Systèmes, École Centrale de Lyon, Lyon, 69130, France
| | - Anja-Verena Mudring
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, SE-114 18, Sweden
- Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C, 8000, Denmark
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Orzechowska M, Rećko K, Klekotka U, Czerniecka M, Tylicki A, Satuła D, Soloviov DV, Beskrovnyy AI, Miaskowski A, Kalska-Szostko B. Structural and Thermomagnetic Properties of Gallium Nanoferrites and Their Influence on Cells In Vitro. Int J Mol Sci 2023; 24:14184. [PMID: 37762487 PMCID: PMC10532423 DOI: 10.3390/ijms241814184] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/03/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Magnetite and gallium substituted cuboferrites with a composition of GaxFe3-xO4 (0 ≤ x ≤ 1.4) were fabricated by thermal decomposition from acetylacetonate salts. The effect of Ga3+ cation substitution on the structural and thermomagnetic behavior of 4-12 nm sized core-shell particles was explored by X-ray and neutron diffraction, small angle neutron scattering, transmission electron microscopy, Mössbauer spectroscopy, and calorimetric measurements. Superparamagnetic (SPM) behavior and thermal capacity against increasing gallium concentration in nanoferrites were revealed. The highest heat capacity typical for Fe3O4@Ga0.6Fe2.4O4 and Ga0.6Fe2.4O4@Fe3O4 is accompanied by a slight stimulation of fibroblast culture growth and inhibition of HeLa cell growth. The observed effect is concentration dependent in the range of 0.01-0.1 mg/mL and particles of Ga0.6Fe2.4O4@Fe3O4 design have a greater effect on cells. Observed magnetic heat properties, as well as interactions with tumor and healthy cells, provide a basis for further biomedical research to use the proposed nanoparticle systems in cancer thermotherapy (magnetic hyperthermia).
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Affiliation(s)
- Marta Orzechowska
- Doctoral School of Exact and Natural Sciences, University of Bialystok, K. Ciołkowskiego 1K, 15-245 Białystok, Poland
| | - Katarzyna Rećko
- Faculty of Physics, University of Bialystok, K. Ciołkowskiego 1L, 15-245 Bialystok, Poland; (K.R.); (D.S.)
| | - Urszula Klekotka
- Faculty of Chemistry, University of Bialystok, K. Ciołkowskiego 1K, 15-245 Białystok, Poland; (U.K.); (B.K.-S.)
| | - Magdalena Czerniecka
- Faculty of Biology, University of Bialystok, K. Ciołkowskiego 1J, 15-245 Białystok, Poland; (M.C.); (A.T.)
| | - Adam Tylicki
- Faculty of Biology, University of Bialystok, K. Ciołkowskiego 1J, 15-245 Białystok, Poland; (M.C.); (A.T.)
| | - Dariusz Satuła
- Faculty of Physics, University of Bialystok, K. Ciołkowskiego 1L, 15-245 Bialystok, Poland; (K.R.); (D.S.)
| | - Dmytro V. Soloviov
- European Molecular Biology Laboratory, Notkestraße 85, 22607 Hamburg, Germany;
| | - Anatoly I. Beskrovnyy
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Russia;
| | - Arkadiusz Miaskowski
- Department of Applied Mathematics and Computer Sciences, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland;
| | - Beata Kalska-Szostko
- Faculty of Chemistry, University of Bialystok, K. Ciołkowskiego 1K, 15-245 Białystok, Poland; (U.K.); (B.K.-S.)
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Horkay F, Basser PJ, Geissler E. Ion-induced changes in DNA gels. Soft Matter 2023; 19:5405-5415. [PMID: 37427607 PMCID: PMC10510426 DOI: 10.1039/d3sm00666b] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Small angle neutron scattering (SANS) measurements are reported for DNA gels under near physiological conditions in which the concentration of monovalent and divalent counter-ions and the pH are varied. The scattering intensity I(q) is described by a two-term equation, one due to osmotic concentration fluctuations and the other coming from static inhomogeneities frozen in by the cross-links. SANS in the low q range indicates the presence of large clusters and the size of which exceeds the resolution of the experiment. In the intermediate q-range, the intensity increases with the CaCl2 concentration and the slope approaches -1, corresponding to linear (rod-like) scatterers. In the highest q region, the scattering response is governed by the local chain geometry. Screening of electrostatic interactions by sodium chloride causes a moderate increase in the SANS intensity that is accompanied by an increase in the mesh size L of the network. Addition of calcium chloride, or a decrease in pH, produces similar trends, and ultimately leads to phase separation. The scattering intensity at q = 0, estimated from independent measurements of the osmotic pressure Π, is in excellent agreement with I(0) from the SANS measurements. Anomalous small angle X-ray scattering (ASAXS) measurements on the uncross-linked DNA show that the monovalent ion cloud is only weakly influenced by the addition of divalent ions. Conversely, the divalent counter-ion cloud tightly follows the contour of polymer chains.
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Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA.
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA.
| | - Erik Geissler
- Laboratoire Interdisciplinaire de Physique, Université Grenoble Alpes and CNRS, F-38000 Grenoble, France
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8
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Shi B, Matsui T, Qian S, Weiss TM, Nicholl ID, Callaway DJE, Bu Z. An ensemble of cadherin-catenin-vinculin complex employs vinculin as the major F-actin binding mode. Biophys J 2023; 122:2456-2474. [PMID: 37147801 PMCID: PMC10323030 DOI: 10.1016/j.bpj.2023.04.026] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/14/2023] [Accepted: 04/27/2023] [Indexed: 05/07/2023] Open
Abstract
The cell-cell adhesion cadherin-catenin complexes recruit vinculin to the adherens junction (AJ) to modulate the mechanical couplings between neighboring cells. However, it is unclear how vinculin influences the AJ structure and function. Here, we identified two patches of salt bridges that lock vinculin in the head-tail autoinhibited conformation and reconstituted the full-length vinculin activation mimetics bound to the cadherin-catenin complex. The cadherin-catenin-vinculin complex contains multiple disordered linkers and is highly dynamic, which poses a challenge for structural studies. We determined the ensemble conformation of this complex using small-angle x-ray and selective deuteration/contrast variation small-angle neutron scattering. In the complex, both α-catenin and vinculin adopt an ensemble of flexible conformations, but vinculin has fully open conformations with the vinculin head and actin-binding tail domains well separated from each other. F-actin binding experiments show that the cadherin-catenin-vinculin complex binds and bundles F-actin. However, when the vinculin actin-binding domain is removed from the complex, only a minor fraction of the complex binds to F-actin. The results show that the dynamic cadherin-catenin-vinculin complex employs vinculin as the primary F-actin binding mode to strengthen AJ-cytoskeleton interactions.
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Affiliation(s)
- Bright Shi
- Department of Chemistry and Biochemistry, City College of New York, City University of New York (CUNY), New York; PhD Programs in Chemistry and Biochemistry, CUNY Graduate Center, New York
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Shuo Qian
- Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Iain D Nicholl
- Department of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, United Kingdom
| | - David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, City University of New York (CUNY), New York.
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, City University of New York (CUNY), New York; PhD Programs in Chemistry and Biochemistry, CUNY Graduate Center, New York.
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9
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Almeida M, Dudzinski D, Amiel C, Guigner JM, Prévost S, Le Coeur C, Cousin F. Aqueous Binary Mixtures of Stearic Acid and Its Hydroxylated Counterpart 12-Hydroxystearic Acid: Cascade of Morphological Transitions at Room Temperature. Molecules 2023; 28:molecules28114336. [PMID: 37298812 DOI: 10.3390/molecules28114336] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/12/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023] Open
Abstract
Here, we describe the behavior of mixtures of stearic acid (SA) and its hydroxylated counterpart 12-hydroxystearic acid (12-HSA) in aqueous mixtures at room temperature as a function of the 12-HSA/SA mole ratio R. The morphologies of the self-assembled aggregates are obtained through a multi-structural approach that combines confocal and cryo-TEM microscopies with small-angle neutron scattering (SANS) and wide-angle X-ray scattering (WAXS) measurements, coupled with rheology measurements. Fatty acids are solubilized by an excess of ethanolamine counterions, so that their heads are negatively charged. A clear trend towards partitioning between the two types of fatty acids is observed, presumably driven by the favorable formation of a H-bond network between hydroxyl OH function on the 12th carbon. For all R, the self-assembled structures are locally lamellar, with bilayers composed of crystallized and strongly interdigitated fatty acids. At high R, multilamellar tubes are formed. The doping via a low amount of SA molecules slightly modifies the dimensions of the tubes and decreases the bilayer rigidity. The solutions have a gel-like behavior. At intermediate R, tubes coexist in solution with helical ribbons. At low R, local partitioning also occurs, and the architecture of the self-assemblies associates the two morphologies of the pure fatty acids systems: they are faceted objects with planar domains enriched in SA molecules, capped with curved domains enriched in 12-HSA molecules. The rigidity of the bilayers is strongly increased, as well their storage modulus. The solutions remain, however, viscous fluids in this regime.
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Affiliation(s)
- Maëva Almeida
- Institut Chimie et Materiaux Paris Est, Université Paris Est Créteil, CNRS, UMR 7182, 2 Rue Henri Dunant, 94320 Thiais, France
- Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS UMR 12 CEA Saclay, 91191 Gif sur Yvette, France
| | - Daniel Dudzinski
- Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS UMR 12 CEA Saclay, 91191 Gif sur Yvette, France
| | - Catherine Amiel
- Institut Chimie et Materiaux Paris Est, Université Paris Est Créteil, CNRS, UMR 7182, 2 Rue Henri Dunant, 94320 Thiais, France
| | - Jean-Michel Guigner
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC)-IRD-MNHN, Sorbonne Université & CNRS, UMR 7590, CEDEX 05, 75252 Paris, France
| | - Sylvain Prévost
- Institut Laue-Langevin-71 Avenue des Martyrs, CS 20156, CEDEX 9, 38042 Grenoble, France
| | - Clémence Le Coeur
- Institut Chimie et Materiaux Paris Est, Université Paris Est Créteil, CNRS, UMR 7182, 2 Rue Henri Dunant, 94320 Thiais, France
- Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS UMR 12 CEA Saclay, 91191 Gif sur Yvette, France
| | - Fabrice Cousin
- Institut Chimie et Materiaux Paris Est, Université Paris Est Créteil, CNRS, UMR 7182, 2 Rue Henri Dunant, 94320 Thiais, France
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10
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Abstract
A novel composite hydrogel was developed that shows remarkable similarities to load bearing biological tissues. The composite gel consisting of a poly(vinyl alcohol (PVA) matrix filled with poly(acrylic acid) (PAA) microgel particles exhibits osmotic and mechanical properties that are qualitatively different from regular gels. In the PVA/PAA system the swollen PAA particles "inflate" the PVA network. The swelling of the PAA is limited by the tensile stress Pel developing in the PVA matrix. Pel increases with increasing swelling degree, which is opposite to the decrease of the elastic pressure observed in regular gels. The maximum tensile stress Pmaxel can be identified as a quantity that defines the load bearing ability of the composite gel. Systematic osmotic swelling pressure measurements have been made on PVA/PAA gels to determine the effects of PVA stiffness, PAA crosslink density, and Ca2+ ion concentration on Pmaxel. It is found that Pmaxel increases with the stiffness of the PVA matrix, and decreases with (i) increasing crosslink density of the PAA and (ii) increasing Ca2+ ion concentration. Small angle neutron scattering (SANS) measurements indicate only a weak interaction between the PVA and PAA gels. It is demonstrated that the osmotic swelling pressure of PVA/PAA composite gels reproduces the osmotic behavior of healthy and osteoarthritic cartilage.
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Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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11
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de Santis A, Scoppola E, Ottaviani MF, Koutsioubas A, Barnsley LC, Paduano L, D’Errico G, Russo Krauss I. Order vs. Disorder: Cholesterol and Omega-3 Phospholipids Determine Biomembrane Organization. Int J Mol Sci 2022; 23:ijms23105322. [PMID: 35628128 PMCID: PMC9140907 DOI: 10.3390/ijms23105322] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 02/06/2023] Open
Abstract
Lipid structural diversity strongly affects biomembrane chemico-physical and structural properties in addition to membrane-associated events. At high concentrations, cholesterol increases membrane order and rigidity, while polyunsaturated lipids are reported to increase disorder and flexibility. How these different tendencies balance in composite bilayers is still controversial. In this study, electron paramagnetic resonance spectroscopy, small angle neutron scattering, and neutron reflectivity were used to investigate the structural properties of cholesterol-containing lipid bilayers in the fluid state with increasing amounts of polyunsaturated omega-3 lipids. Either the hybrid 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine or the symmetric 1,2-docosahexaenoyl-sn-glycero-3-phosphocholine were added to the mixture of the naturally abundant 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine and cholesterol. Our results indicate that the hybrid and the symmetric omega-3 phospholipids affect the microscopic organization of lipid bilayers differently. Cholesterol does not segregate from polyunsaturated phospholipids and, through interactions with them, is able to suppress the formation of non-lamellar structures induced by the symmetric polyunsaturated lipid. However, this order/disorder balance leads to a bilayer whose structural organization cannot be ascribed to either a liquid ordered or to a canonical liquid disordered phase, in that it displays a very loose packing of the intermediate segments of lipid chains.
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Affiliation(s)
- Augusta de Santis
- Department of Chemical Sciences, University of Naples Federico II, I-80126 Naples, Italy; (A.d.S.); (L.P.)
- CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), I-50019 Florence, Italy
| | - Ernesto Scoppola
- Max Planck Institut für Kolloid und Grenzflächenforschung, 14476 Potsdam, Germany;
| | | | - Alexandros Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany; (A.K.); (L.C.B.)
| | - Lester C. Barnsley
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany; (A.K.); (L.C.B.)
- Australian Synchrotron, ANSTO, Clayton 3168, Australia
| | - Luigi Paduano
- Department of Chemical Sciences, University of Naples Federico II, I-80126 Naples, Italy; (A.d.S.); (L.P.)
- CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), I-50019 Florence, Italy
| | - Gerardino D’Errico
- Department of Chemical Sciences, University of Naples Federico II, I-80126 Naples, Italy; (A.d.S.); (L.P.)
- CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), I-50019 Florence, Italy
- Correspondence: (G.D.); (I.R.K.)
| | - Irene Russo Krauss
- Department of Chemical Sciences, University of Naples Federico II, I-80126 Naples, Italy; (A.d.S.); (L.P.)
- CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), I-50019 Florence, Italy
- Correspondence: (G.D.); (I.R.K.)
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12
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Holderer O, Koutsioubas A, Garvey CJ, Nylander T. Editorial: Membrane Structure and Dynamics Studied With Neutron Scattering. Front Chem 2021; 9:732062. [PMID: 34490212 PMCID: PMC8417354 DOI: 10.3389/fchem.2021.732062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/06/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- O Holderer
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany
| | - A Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany
| | - C J Garvey
- Lund Institute for Advanced Neutron and X-ray Science, Lund, Sweden.,Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching, Germany
| | - T Nylander
- Lund Institute for Advanced Neutron and X-ray Science, Lund, Sweden.,Department of Chemistry, Lund University, Lund, Sweden
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13
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Sharratt WN, Lopez CG, Sarkis M, Tyagi G, O’Connell R, Rogers SE, Cabral JT. Ionotropic Gelation Fronts in Sodium Carboxymethyl Cellulose for Hydrogel Particle Formation. Gels 2021; 7:44. [PMID: 33921260 PMCID: PMC8167666 DOI: 10.3390/gels7020044] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 11/17/2022] Open
Abstract
Hydrogel microparticles (HMPs) find numerous practical applications, ranging from drug delivery to tissue engineering. Designing HMPs from the molecular to macroscopic scales is required to exploit their full potential as functional materials. Here, we explore the gelation of sodium carboxymethyl cellulose (NaCMC), a model anionic polyelectrolyte, with Fe3+ cations in water. Gelation front kinetics are first established using 1D microfluidic experiments, and effective diffusive coefficients are found to increase with Fe3+ concentration and decrease with NaCMC concentrations. We use Fourier Transform Infrared Spectroscopy (FTIR) to elucidate the Fe3+-NaCMC gelation mechanism and small angle neutron scattering (SANS) to spatio-temporally resolve the solution-to-network structure during front propagation. We find that the polyelectrolyte chain cross-section remains largely unperturbed by gelation and identify three hierarchical structural features at larger length scales. Equipped with the understanding of gelation mechanism and kinetics, using microfluidics, we illustrate the fabrication of range of HMP particles with prescribed morphologies.
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Affiliation(s)
- William N. Sharratt
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK; (M.S.); (G.T.); (R.O.)
| | - Carlos G. Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany;
| | - Miriam Sarkis
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK; (M.S.); (G.T.); (R.O.)
| | - Gunjan Tyagi
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK; (M.S.); (G.T.); (R.O.)
| | - Róisín O’Connell
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK; (M.S.); (G.T.); (R.O.)
| | - Sarah E. Rogers
- ISIS, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, UK;
| | - João T. Cabral
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK; (M.S.); (G.T.); (R.O.)
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14
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Pink DL, Loruthai O, Ziolek RM, Terry AE, Barlow DJ, Lawrence MJ, Lorenz CD. Interplay of lipid and surfactant: Impact on nanoparticle structure. J Colloid Interface Sci 2021; 597:278-288. [PMID: 33872884 DOI: 10.1016/j.jcis.2021.03.136] [Citation(s) in RCA: 9] [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: 11/02/2020] [Revised: 02/15/2021] [Accepted: 03/24/2021] [Indexed: 11/24/2022]
Abstract
Liquid lipid nanoparticles (LLN) are oil-in-water nanoemulsions of great interest in the delivery of hydrophobic drug molecules. They consist of a surfactant shell and a liquid lipid core. The small size of LLNs makes them difficult to study, yet a detailed understanding of their internal structure is vital in developing stable drug delivery vehicles (DDVs). Here, we implement machine learning techniques alongside small angle neutron scattering experiments and molecular dynamics simulations to provide critical insight into the conformations and distributions of the lipid and surfactant throughout the LLN. We simulate the assembly of a single LLN composed of the lipid, triolein (GTO), and the surfactant, Brij O10. Our work shows that the addition of surfactant is pivotal in the formation of a disordered lipid core; the even coverage of Brij O10 across the LLN shields the GTO from water and so the lipids adopt conformations that reduce crystallisation. We demonstrate the superior ability of unsupervised artificial neural networks in characterising the internal structure of DDVs, when compared to more conventional geometric methods. We have identified, clustered, classified and averaged the dominant conformations of lipid and surfactant molecules within the LLN, providing a multi-scale picture of the internal structure of LLNs.
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Affiliation(s)
- Demi L Pink
- Biological Physics and Soft Matter Group, Department of Physics, King's College London, London, WC2R 2LS, United Kingdom
| | - Orathai Loruthai
- Pharmaceutical Biophysics Group, Institute of Pharmaceutical Science, King's College London, London, SW1 9NH, United Kingdom
| | - Robert M Ziolek
- Biological Physics and Soft Matter Group, Department of Physics, King's College London, London, WC2R 2LS, United Kingdom
| | - Ann E Terry
- CoSAXS beamline, MAX IV Laboratory, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden
| | - David J Barlow
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Stopford Building, Oxford Road, Manchester, United Kingdom
| | - M Jayne Lawrence
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Stopford Building, Oxford Road, Manchester, United Kingdom.
| | - Christian D Lorenz
- Biological Physics and Soft Matter Group, Department of Physics, King's College London, London, WC2R 2LS, United Kingdom.
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15
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Papagiannopoulos A, Pippa N, Demetzos C, Pispas S, Radulescu A. Formation of Uni-Lamellar Vesicles in Mixtures of DPPC with PEO-b-PCL Amphiphilic Diblock Copolymers. Polymers (Basel) 2020; 13:E4. [PMID: 33375022 DOI: 10.3390/polym13010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 12/19/2022] Open
Abstract
The ability of mixtures of 1.2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and the amphiphilic diblock copolymers poly (ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) to stabilize uni-lamellar nano-vesicles is reported. Small angle neutron scattering (SANS) is used to define their size distribution and bilayer structure and resolve the copresence of aggregates and clusters in solution. The vesicles have a broad size distribution which is compatible with bilayer membranes of relatively low bending stiffness. Their mean diameter increases moderately with temperature and their number density and mass is higher in the case of the diblock copolymer with the larger hydrophobic block. Bayesian analysis is performed in order to justify the use of the particular SANS fitting model and confirm the reliability of the extracted parameters. This study shows that amphiphilic block copolymers can be effectively used to prepare mixed lipid-block copolymer vesicles with controlled lamellarity and a significant potential as nanocarriers for drug delivery.
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16
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Arrighi V, Higgins JS. Local Effects of Ring Topology Observed in Polymer Conformation and Dynamics by Neutron Scattering-A Review. Polymers (Basel) 2020; 12:E1884. [PMID: 32825628 DOI: 10.3390/polym12091884] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 11/24/2022] Open
Abstract
The physical properties of polymers depend on a range of both structural and chemical parameters, and in particular, on molecular topology. Apparently simple changes such as joining chains at a point to form stars or simply joining the two ends to form a ring can profoundly alter molecular conformation and dynamics, and hence properties. Cyclic polymers, as they do not have free ends, represent the simplest model system where reptation is completely suppressed. As a consequence, there exists a considerable literature and several reviews focused on high molecular weight cyclics where long range dynamics described by the reptation model comes into play. However, this is only one area of interest. Consideration of the conformation and dynamics of rings and chains, and of their mixtures, over molecular weights ranging from tens of repeat units up to and beyond the onset of entanglements and in both solution and melts has provided a rich literature for theory and simulation. Experimental work, particularly neutron scattering, has been limited by the difficulty of synthesizing well-characterized ring samples, and deuterated analogues. Here in the context of the broader literature we review investigations of local conformation and dynamics of linear and cyclic polymers, concentrating on poly(dimethyl siloxane) (PDMS) and covering a wide range of generally less high molar masses. Experimental data from small angle neutron scattering (SANS) and quasi-elastic neutron scattering (QENS), including Neutron Spin Echo (NSE), are compared to theory and computational predictions.
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17
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Pink DL, Loruthai O, Ziolek RM, Wasutrasawat P, Terry AE, Lawrence MJ, Lorenz CD. On the Structure of Solid Lipid Nanoparticles. Small 2019; 15:e1903156. [PMID: 31532892 DOI: 10.1002/smll.201903156] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Solid lipid nanoparticles (SLNs) have a crystalline lipid core which is stabilized by interfacial surfactants. SLNs are considered favorable candidates for drug delivery vehicles since their ability to store and release organic molecules can be tailored through the identity of the lipids and surfactants used. When stored, polymorphic transitions in the core of drug-loaded SLNs lead to the premature release of drug molecules. Significant experimental studies have been conducted with the aim of investigating the physicochemical properties of SLNs, however, no molecular scale investigations have been reported on the behaviors that drive SLN formation and their polymorphic transitions. A combination of small angle neutron scattering and all-atom molecular dynamics simulations is therefore used to yield a detailed atomistic description of the internal structure of an SLN comprising triglyceride, tripalmitin, and the nonionic surfactant, Brij O10 (C18:1 E10 ). The molecular scale mechanisms by which the surfactants stabilize the crystalline structure of the SLN lipid core are uncovered. By comparing these results to simulated liquid and solid aggregates of tripalmitin lipids, how the morphology of the lipids vary between these systems is demonstrated providing further insight into the mechanisms that control drug encapsulation and release from SLNs.
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Affiliation(s)
- Demi L Pink
- Department of Physics, King's College London, London, WC2R 2LS, UK
| | - Orathai Loruthai
- Pharmaceutical Biophysics Group, Institute of Pharmaceutical Science, King's College London, London, SW1 9NH, UK
| | - Robert M Ziolek
- Department of Physics, King's College London, London, WC2R 2LS, UK
| | - Prawarisa Wasutrasawat
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Ann E Terry
- CoSAXS Beamline, MAX IV Laboratory, Lund University, SE-221 00, Lund, Sweden
| | - M Jayne Lawrence
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, UK
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18
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Festa G, Mallamace F, Sancesario GM, Corsaro C, Mallamace D, Fazio E, Arcidiacono L, Garcia Sakai V, Senesi R, Preziosi E, Sancesario G, Andreani C. Aggregation States of A β1-40, A β1-42 and A βp 3-42 Amyloid Beta Peptides: A SANS Study. Int J Mol Sci 2019; 20:ijms20174126. [PMID: 31450543 PMCID: PMC6747079 DOI: 10.3390/ijms20174126] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 11/16/2022] Open
Abstract
Aggregation states of amyloid beta peptides for amyloid beta A β 1 - 40 to A β 1 - 42 and A β p 3 - 42 are investigated through small angle neutron scattering (SANS). The knowledge of these small peptides and their aggregation state are of key importance for the comprehension of neurodegenerative diseases (e.g., Alzheimer's disease). The SANS technique allows to study the size and fractal nature of the monomers, oligomers and fibrils of the three different peptides. Results show that all the investigated peptides have monomers with a radius of gyration of the order of 10 Å, while the oligomers and fibrils display differences in size and aggregation ability, with A β p 3 - 42 showing larger oligomers. These properties are strictly related to the toxicity of the corresponding amyloid peptide and indeed to the development of the associated disease.
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Affiliation(s)
- Giulia Festa
- CENTRO FERMI-Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", 00184 Rome, Italy
| | - Francesco Mallamace
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Giulia Maria Sancesario
- IRCCS Fondazione Santa Lucia, 00142 Rome, Italy
- Department of Experimental Medicine and Surgery, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy
| | - Carmelo Corsaro
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina, Italy.
| | - Domenico Mallamace
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina, Italy.
| | - Enza Fazio
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina, Italy
| | - Laura Arcidiacono
- CENTRO FERMI-Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", 00184 Rome, Italy
- Science and Technology Facilities Council, ISIS Pulsed Neutron and Muon Source, Didcot OX11 0QX, UK
| | - Victoria Garcia Sakai
- Science and Technology Facilities Council, ISIS Pulsed Neutron and Muon Source, Didcot OX11 0QX, UK
| | - Roberto Senesi
- CENTRO FERMI-Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", 00184 Rome, Italy
- NAST Centre and Department of Physics, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy
| | - Enrico Preziosi
- NAST Centre and Department of Physics, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy
| | - Giuseppe Sancesario
- Department of Systems Medicine, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy
| | - Carla Andreani
- CENTRO FERMI-Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", 00184 Rome, Italy
- NAST Centre and Department of Physics, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy
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19
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Mussel M, Basser PJ, Horkay F. Effects of mono- and divalent cations on the structure and thermodynamic properties of polyelectrolyte gels. Soft Matter 2019; 15:4153-4161. [PMID: 31062008 PMCID: PMC6531340 DOI: 10.1039/c9sm00464e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Measurements are reported on the effect of monovalent and divalent salts on the swelling behavior and supramolecular structure of sodium polyacrylate gels (NaPA) made by osmotic swelling pressure and small angle neutron scattering measurements. The swelling response of the gels in solutions of ten different monovalent salts is found to be practically identical indicating that the principal effect of monovalent ions is screening the electrostatic repulsion among the charged groups on the polyelectrolyte chains; i.e., chemical differences between the monovalent ions do not play a significant role. Introducing Ca2+ ions into the equilibrium NaCl solution results in a sharp volume transition of the gels. The threshold Ca2+ ion concentration at which the transition occurs increases with increasing NaCl concentration in the surrounding bath. It is demonstrated that the swelling behavior of NaPA gels exhibits universal properties in solutions containing both NaCl and CaCl2. Osmotic swelling pressure measurements reveal that both the second and third virial coefficients decrease with increasing CaCl2 concentration until the volume transition is reached. The macroscopic measurements are complemented by small angle neutron scattering that reveals the variation of the thermodynamic length scales as the volume transition is approached. The thermodynamic correlation length L increases with increasing CaCl2 concentration.
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20
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Simm TH, Sun L, Galvin DR, Hill P, Rawson M, Birosca S, Gilbert EP, Bhadeshia H, Perkins K. The Effect of a Two-Stage Heat-Treatment on the Microstructural and Mechanical Properties of a Maraging Steel. Materials (Basel) 2017; 10:ma10121346. [PMID: 29168800 PMCID: PMC5744281 DOI: 10.3390/ma10121346] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/18/2017] [Accepted: 11/20/2017] [Indexed: 11/16/2022]
Abstract
Maraging steels gain many of their beneficial properties from heat treatments which induce the precipitation of intermetallic compounds. We consider here a two-stage heat-treatment, first involving austenitisation, followed by quenching to produce martensite and then an ageing treatment at a lower temperature to precipitation harden the martensite of a maraging steel. It is shown that with a suitable choice of the initial austenitisation temperature, the steel can be heat treated to produce enhanced toughness, strength and creep resistance. A combination of small angle neutron scattering, scanning electron microscopy, electron back-scattered diffraction, and atom probe tomography were used to relate the microstructural changes to mechanical properties. It is shown that such a combination of characterisation methods is necessary to quantify this complex alloy, and relate these microstructural changes to mechanical properties. It is concluded that a higher austenitisation temperature leads to a greater volume fraction of smaller Laves phase precipitates formed during ageing, which increase the strength and creep resistance but reduces toughness.
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Affiliation(s)
| | - Lin Sun
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK.
| | - Deri Rhys Galvin
- College of Engineering, Swansea University, Swansea SA1 8EN, UK.
| | - Paul Hill
- Rolls-Royce plc, P.O. Box 31, Derby DE24 8BJ, UK.
| | | | - Soran Birosca
- College of Engineering, Swansea University, Swansea SA1 8EN, UK.
| | - Elliot Paul Gilbert
- The Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights NSW 2234, Australia.
| | - Harshad Bhadeshia
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK.
| | - Karen Perkins
- College of Engineering, Swansea University, Swansea SA1 8EN, UK.
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21
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Steinschulte AA, Scotti A, Rahimi K, Nevskyi O, Oppermann A, Schneider S, Bochenek S, Schulte MF, Geisel K, Jansen F, Jung A, Mallmann S, Winter R, Richtering W, Wöll D, Schweins R, Warren NJ, Plamper FA. Stimulated Transitions of Directed Nonequilibrium Self-Assemblies. Adv Mater 2017; 29:1703495. [PMID: 29024083 DOI: 10.1002/adma.201703495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/17/2017] [Indexed: 06/07/2023]
Abstract
Near-equilibrium stimulus-responsive polymers have been used extensively to introduce morphological variations in dependence of adaptable conditions. Far-less-well studied are triggered transformations at constant conditions. These require the involvement of metastable states, which are either able to approach the equilibrium state after deviation from metastability or can be frozen on returning from nonequilibrium to equilibrium. Such functional nonequilibrium macromolecular systems hold great promise for on-demand transformations, which result in substantial changes in their material properties, as seen for triggered gelations. Herein, a diblock copolymer system consisting of a hydrophilic block and a block that is responsive to both pressure and temperature, is introduced. This species demonstrates various micellar transformations upon leaving equilibrium/nonequilibrium states, which are triggered by a temperature deflection or a temporary application of hydrostatic pressure.
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Affiliation(s)
| | - Andrea Scotti
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Khosrow Rahimi
- DWI Leibniz Institute for Interactive Materials and Center for Chemical Polymer Technology (CPT), Forckenbeckstr. 50, D-52074, Aachen, Germany
| | - Oleksii Nevskyi
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Alex Oppermann
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Sabine Schneider
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Steffen Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Marie F Schulte
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Karen Geisel
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Felicitas Jansen
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Andre Jung
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Sabrina Mallmann
- DWI Leibniz Institute for Interactive Materials and Center for Chemical Polymer Technology (CPT), Forckenbeckstr. 50, D-52074, Aachen, Germany
| | - Roland Winter
- Department of Chemistry and Chemical Biology, Physical Chemistry I, TU Dortmund University, Otto-Hahn Str. 6, D-44227, Dortmund, Germany
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Dominik Wöll
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Ralf Schweins
- Institut Laue-Langevin ILL, DS/LSS, 71 Avenue des Martyrs, F-38000, Grenoble, France
| | - Nicholas J Warren
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Felix A Plamper
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
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22
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Abstract
The most abundant cartilage proteoglycan is aggrecan, a bottlebrush shaped molecule that possesses over 100 glycosaminoglycan (chondroitin sulfate and keratan sulfate) chains. The side-chains are linear sulfated polysaccharides that are negatively charged under physiological conditions. Aggrecan interacts with hyaluronic acid (HA) to form large aggregates. Osmotic pressure measurements and rheological measurements are used to study the static and dynamic behavior of aggrecan assemblies at the macroscopic length scales. The microscopic properties of aggrecan solutions are determined by small angle neutron scattering (SANS), and static and dynamic light scattering (SLS and DLS). In dilute solutions aggrecan forms microgels with a diffuse boundary, composed of loosely connected clusters. The osmotic pressure of the aggrecan-HA system decreases with increasing HA content. DLS yields a relaxation rate that varies as q3, arising from internal modes in the microgel. The relaxation rate in the solutions of the aggrecan-HA complex is slightly greater than in the pure aggrecan solution.
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Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Schriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Schriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA
| | - Anne-Marie Hecht
- Laboratoire de Spectrométrie Physique CNRS UMR 5588, Université J. Fourier de Grenoble, B.P.87, 38402 St Martin d'Hères cedex, France
| | - Erik Geissler
- Laboratoire de Spectrométrie Physique CNRS UMR 5588, Université J. Fourier de Grenoble, B.P.87, 38402 St Martin d'Hères cedex, France
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23
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Gao Y, Nieuwendaal R, Dimitriadis EK, Hammouda B, Douglas JF, Xu B, Horkay F. Supramolecular Self-assembly of a Model Hydrogelator: Characterization of Fiber Formation and Morphology. Gels 2016; 2:27. [PMID: 28649573 PMCID: PMC5482529 DOI: 10.3390/gels2040027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/22/2016] [Indexed: 11/16/2022] Open
Abstract
Hydrogels are of intense recent interest in connection with biomedical applications ranging from 3-D cell cultures and stem cell differentiation to regenerative medicine, controlled drug delivery and tissue engineering. This prototypical form of soft matter has many emerging material science applications outside the medical field. The physical processes underlying this type of solidification are incompletely understood and this limits design efforts aimed at optimizing these materials for applications. We address this general problem by applying multiple techniques (e.g., NMR, dynamic light scattering, small angle neutron scattering, rheological measurements) to the case of a peptide derivative hydrogelator (molecule 1, NapFFKYp) over a broad range of concentration and temperature to characterize both the formation of individual nanofibers and the fiber network. We believe that a better understanding of the hierarchical self-assembly process and control over the final morphology of this kind of material should have broad significance for biological and medicinal applications utilizing hydrogels.
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Affiliation(s)
- Yuan Gao
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
| | - Ryan Nieuwendaal
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
| | - Emilios K. Dimitriadis
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Boualem Hammouda
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
| | - Bing Xu
- Department of Chemistry, Brandeis University, Waltham, MA 02453, USA;
| | - Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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24
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Richards JJ, Scherbarth AD, Wagner NJ, Butler PD. Mixed Ionic/Electronic Conducting Surface Layers Adsorbed on Colloidal Silica for Flow Battery Applications. ACS Appl Mater Interfaces 2016; 8:24089-24096. [PMID: 27536887 DOI: 10.1021/acsami.6b07372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
UNLABELLED Slurry based electrodes have shown promise as an energy dense and scalable storage technology for electrochemical flow batteries. Key to their efficient operation is the use of a conductive additive which allows for volumetric charging and discharging of the electrochemically active species contained within the electrodes. Carbon black is commonly used for this purpose due to the relatively low concentrations needed to maintain electrical percolation. While carbon black supplies the desirable electrical properties for the application, it contributes detrimentally to the rheology characteristics of these concentrated suspensions. In this work, we develop a synthesis protocol to produce inorganic oxide particles with electrostatically adsorbed poly(3,4-ethylenedioxithiophene):polystyrenesulfonate ( PEDOT PSS). Using a combination of small angle neutron scattering (SANS), electron microscopy, and thin-film conductivity, we show that the synthesis scheme provides a flexible platform to form conductive PEDOT PSS-SiO2 nanoparticle dispersions. Based on these measurements, we demonstrate that these particles are stable when dispersed in propylene carbonate. Using a combination of rheology and dielectric spectroscopy, we show that these stable dispersions facilitate electrical percolation at concentrations below their mechanical percolation threshold, and this percolation is maintained under flow. These results demonstrate the potential for strategies which seek to decouple mechanical and electrical percolation to allow for the development of higher performance conductive additives for slurry based flow batteries.
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Affiliation(s)
- Jeffrey J Richards
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Austin D Scherbarth
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Norman J Wagner
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 98195, United States
| | - Paul D Butler
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 98195, United States
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25
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Hennig J, Sattler M. The dynamic duo: combining NMR and small angle scattering in structural biology. Protein Sci 2014; 23:669-82. [PMID: 24687405 DOI: 10.1002/pro.2467] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [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: 03/06/2014] [Revised: 03/25/2014] [Accepted: 03/28/2014] [Indexed: 12/12/2022]
Abstract
Structural biology provides essential information for elucidating molecular mechanisms that underlie biological function. Advances in hardware, sample preparation, experimental methods, and computational approaches now enable structural analysis of protein complexes with increasing complexity that more closely represent biologically entities in the cellular environment. Integrated multidisciplinary approaches are required to overcome limitations of individual methods and take advantage of complementary aspects provided by different structural biology techniques. Although X-ray crystallography remains the method of choice for structural analysis of large complexes, crystallization of flexible systems is often difficult and does typically not provide insights into conformational dynamics present in solution. Nuclear magnetic resonance spectroscopy (NMR) is well-suited to study dynamics at picosecond to second time scales, and to map binding interfaces even of large systems at residue resolution but suffers from poor sensitivity with increasing molecular weight. Small angle scattering (SAS) methods provide low resolution information in solution and can characterize dynamics and conformational equilibria complementary to crystallography and NMR. The combination of NMR, crystallography, and SAS is, thus, very useful for analysis of the structure and conformational dynamics of (large) protein complexes in solution. In high molecular weight systems, where NMR data are often sparse, SAS provides additional structural information and can differentiate between NMR-derived models. Scattering data can also validate the solution conformation of a crystal structure and indicate the presence of conformational equilibria. Here, we review current state-of-the-art approaches for combining NMR, crystallography, and SAS data to characterize protein complexes in solution.
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Affiliation(s)
- Janosch Hennig
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr.1, D-85764, Neuherberg, Germany; Center for Integrated Protein Science Munich at Chair Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747, Garching, Germany
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26
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Teixeira SCM, Ankner J, Bellissent-Funel MC, Bewley R, Blakeley MP, Coates L, Dahint R, Dalgliesh R, Dencher N, Dhont J, Fischer P, Forsyth VT, Fragneto G, Frick B, Geue T, Gilles R, Gutberlet T, Haertlein M, Hauß T, Häußler W, Heller WT, Herwig K, Holderer O, Juranyi F, Kampmann R, Knott R, Kohlbrecher J, Kreuger S, Langan P, Lechner R, Lynn G, Majkrzak C, May R, Meilleur F, Mo Y, Mortensen K, Myles DAA, Natali F, Neylon C, Niimura N, Ollivier J, Ostermann A, Peters J, Pieper J, Rühm A, Schwahn D, Shibata K, Soper AK, Straessle T, Suzuki UI, Tanaka I, Tehei M, Timmins P, Torikai N, Unruh T, Urban V, Vavrin R, Weiss K, Zaccai G. New sources and instrumentation for neutrons in biology. Chem Phys 2009; 345:133-151. [PMID: 19132140 PMCID: PMC2614686 DOI: 10.1016/j.chemphys.2008.02.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.
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Affiliation(s)
- S C M Teixeira
- Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble cedex 9, France
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27
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Nakatani AI, Kim H, Han CC. Apparatus for Simultaneous Small Angle Neutron Scattering and Steady Shear Viscosity Studies of Polymer Melts and Solutions. J Res Natl Inst Stand Technol 1990; 95:7-14. [PMID: 28179754 PMCID: PMC4948927 DOI: 10.6028/jres.095.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/03/1989] [Indexed: 05/29/2023]
Abstract
The design and construction of an apparatus for studying the simultaneous small angle neutron scattering (SANS) and steady shear viscosity behavior of polymer melts and concentrated solutions is discussed. Successful operation of the device is demonstrated on a blend of 20 weight percent deuterated polystyrene and 80 weight percent poly(vinylmethylether). The effects of shear on the critical behavior of the blend are observed in the SANS behavior as a function of temperature and shear rate and indicate shear induced mixing behavior for the range of shear rates examined. The steady shear viscosity results alone are insufficient for detecting the transition from one to two phases. The examination of shear effects in polymer blends is important for understanding the critical behavior of binary systems. Technologically, knowledge of the phase behavior of polymer blends under shear are important for the design and improvement of commercial blend processing.
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Affiliation(s)
- Alan I Nakatani
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Hongdoo Kim
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Charles C Han
- National Institute of Standards and Technology, Gaithersburg, MD 20899
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28
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Fuller ER, Fields RJ, Chuang TJ, Singhal S. Characterization of Creep Damage in Metals Using Small Angle Neutron Scattering. J Res Natl Bur Stand (1977) 1984; 89:35-45. [PMID: 34566117 PMCID: PMC6768172 DOI: 10.6028/jres.089.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Creep damage in polycrystalline metallic materials can be attributed to cavitation and cracking along the grain interfaces. Theories of creep cavitation that have been developed in recent years are reviewed. Further evaluation and/or refinement of these theories has been retarded by a lack of an experimental counterpart. Small angle neutron scattering studies (SANS) provide one experimental tool which is complementary to others. SANS done at NBS and elsewhere have shown that this technique is suitable for studying nucleation and early stage of growth of creep cavities. This would provide the impetus to further progress in this area.
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Affiliation(s)
- E R Fuller
- National Bureau of Standards, Washington, DC 20234
| | - R J Fields
- National Bureau of Standards, Washington, DC 20234
| | - T-J Chuang
- National Bureau of Standards, Washington, DC 20234
| | - S Singhal
- National Bureau of Standards, Washington, DC 20234
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29
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Hardman-Rhyne K, Berk NF, Fuller ER. Microstructural Characterization of Ceramic Materials by Small Angle Neutron Scattering Techniques. J Res Natl Bur Stand (1977) 1984; 89:17-34. [PMID: 34566116 DOI: 10.6028/jres.089.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The use of small angle neutron scattering (SANS) techniques for ceramic materials is discussed. Two areas are emphasized: 1) diffraction for microstructural phenomena of less than 100 nm, and 2) beam broadening for microstructural phenomena greater than 90 nm.
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Affiliation(s)
| | - N F Berk
- National Bureau of Standards, Washington, DC 20234
| | - E R Fuller
- National Bureau of Standards, Washington, DC 20234
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