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Lu D, Chai A, Hu X, Zhong P, Kang N, Kuang X, Yang Z. Conformational Transition of Semiflexible Ring Polyelectrolyte in Tetravalent Salt Solutions: A Simple Numerical Modeling without the Effect of Twisting. Int J Mol Sci 2024; 25:8268. [PMID: 39125837 PMCID: PMC11311450 DOI: 10.3390/ijms25158268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/23/2024] [Accepted: 07/25/2024] [Indexed: 08/12/2024] Open
Abstract
In this work, the conformational behaviors of ring polyelectrolyte in tetravalent salt solutions are discussed in detail through molecular dynamics simulation. For simplification, here we have neglected the effect of the twisting interaction, although it has been well known that both bending and twisting interactions play a deterministic in the steric conformation of a semiflexible ring polymer. The salt concentration CS and the bending energy b take a decisive role in the conformation of the ring polyelectrolyte (PE). Throughout our calculations, the b varies from b = 0 (freely joint chain) to b = 120. The salt concentration CS changes in the range of 3.56 × 10-4 M ≤ CS ≤ 2.49 × 10-1 M. Upon the addition of salt, ring PE contracts at first, subsequently re-expands. More abundant conformations are observed for a semiflexible ring PE. For b = 10, the conformation of semiflexible ring PE shifts from the loop to two-racquet-head spindle, then it condenses into toroid, finally arranges into coil with the increase of CS. As b increases further, four phase transitions are observed. The latter two phase transitions are different. The semiflexible ring PE experiences transformation from toroid to two racquet head spindle, finally to loop in the latter two phase transitions. Its conformation is determined by the competition among the bending energy, cation-bridge, and entropy. Combined, our findings indicate that the conformations of semiflexible ring PE can be controlled by changing the salt concentration and chain stiffness.
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Affiliation(s)
- Dan Lu
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (D.L.); (X.H.); (N.K.); (X.K.)
| | - Aihua Chai
- College of Data Sience, Jiaxing University, Jiaxing 314001, China;
| | - Xiuxia Hu
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (D.L.); (X.H.); (N.K.); (X.K.)
| | - Peihua Zhong
- College of Computer Information and Engineering, Jiangxi Agricultural University, Nanchang 330045, China;
| | - Nianqian Kang
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (D.L.); (X.H.); (N.K.); (X.K.)
| | - Xianfei Kuang
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (D.L.); (X.H.); (N.K.); (X.K.)
| | - Zhiyong Yang
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (D.L.); (X.H.); (N.K.); (X.K.)
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Varela-Feijoo A, Djemia P, Narita T, Pignon F, Baeza-Squiban A, Sirri V, Ponton A. Multiscale investigation of viscoelastic properties of aqueous solutions of sodium alginate and evaluation of their biocompatibility. SOFT MATTER 2023; 19:5942-5955. [PMID: 37490024 DOI: 10.1039/d3sm00159h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
In order to get better knowledge of mechanical properties from microscopic to macroscopic scale of biopolymers, viscoelastic bulk properties of aqueous solutions of sodium alginate were studied at different scales by combining macroscopic shear rheology (Hz), diffusing-wave spectroscopy microrheology (kHz-MHz) and Brillouin spectroscopy (GHz). Structural properties were also directly probed by small-angle X-ray scattering (SAXS). The results demonstrate a change from polyelectrolyte behavior to neutral polymer behavior by increasing polymer concentration with the determination of characteristic sizes (persistence length, correlation length). The viscoelastic properties probed at the phonon wavelength much higher than the ones obtained at low frequency reflect the variation of microscopic viscosity. First experiments obtained by metabolic activity assays with mouse embryonic fibroblasts showed biocompatibility of sodium alginate aqueous solutions in the studied range of concentrations (2.5-10 g L-1) and consequently their potential biomedical applications.
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Affiliation(s)
- Alberto Varela-Feijoo
- Laboratoire Matière et systèmes complexes (MSC), Université Paris Cité et CNRS, UMR 7057, 10 rue A. Domon et L. Duquet, 75013 Paris, France.
- Université Paris Saclay, INRAE, AgroParisTech, UMR SayFood, 91120 Palaiseau, France
| | - Philippe Djemia
- Laboratoire des Sciences des procédés et des matériaux (LSPM), UPR-CNRS 3407, 99 Avenue Jean-Baptiste Clément, 93530 Villetaneuse, France
| | - Tetsuharu Narita
- École supérieure de physique et de chimie industrielles de la ville de Paris (ESPCI), 10 Rue Vauquelin, 75005 Paris, France
| | - Frédéric Pignon
- Laboratoire rhéologie et procédés (LPG) Université Grenoble Alpes, CNRS, UMR 5520, Domaine Universitaire, BP 53, 38041 Grenoble Cedex 9, France
| | - Armelle Baeza-Squiban
- Unité de Biologie fonctionnelle et adaptative (BFA), Université Paris Cité et CNRS, UMR 8251, 4 rue Marie-Andrée Lagroua Weill-Hallé, 75013 Paris, France
| | - Valentina Sirri
- Unité de Biologie fonctionnelle et adaptative (BFA), Université Paris Cité et CNRS, UMR 8251, 4 rue Marie-Andrée Lagroua Weill-Hallé, 75013 Paris, France
| | - Alain Ponton
- Laboratoire Matière et systèmes complexes (MSC), Université Paris Cité et CNRS, UMR 7057, 10 rue A. Domon et L. Duquet, 75013 Paris, France.
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Concentration Dependent Single Chain Properties of Poly(sodium 4-styrenesulfonate) Subjected to Aromatic Interactions with Chlorpheniramine Maleate Studied by Diafiltration and Synchrotron-SAXS. Polymers (Basel) 2021; 13:polym13203563. [PMID: 34685324 PMCID: PMC8538281 DOI: 10.3390/polym13203563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/26/2021] [Accepted: 10/01/2021] [Indexed: 11/17/2022] Open
Abstract
The polyelectrolyte poly(sodium 4-styrenesulfonate) undergoes aromatic–aromatic interaction with the drug chlorpheniramine, which acts as an aromatic counterion. In this work, we show that an increase in the concentration in the dilute and semidilute regimes of a complex polyelectrolyte/drug 2:1 produces the increasing confinement of the drug in hydrophobic domains, with implications in single chain thermodynamic behavior. Diafiltration analysis at polymer concentrations between 0.5 and 2.5 mM show an increase in the fraction of the aromatic counterion irreversibly bound to the polyelectrolyte, as well as a decrease in the electrostatic reversible interaction forces with the remaining fraction of drug molecules as the total concentration of the system increases. Synchrotron-SAXS results performed in the semidilute regimes show a fractal chain conformation pattern with a fractal dimension of 1.7, similar to uncharged polymers. Interestingly, static and fractal correlation lengths increase with increasing complex concentration, due to the increase in the amount of the confined drug. Nanoprecipitates are found in the range of 30–40 mM, and macroprecipitates are found at a higher system concentration. A model of molecular complexation between the two species is proposed as the total concentration increases, which involves ion pair formation and aggregation, producing increasingly confined aromatic counterions in hydrophobic domains, as well as a decreasing number of charged polymer segments at the hydrophobic/hydrophilic interphase. All of these features are of pivotal importance to the general knowledge of polyelectrolytes, with implications both in fundamental knowledge and potential technological applications considering aromatic-aromatic binding between aromatic polyelectrolytes and aromatic counterions, such as in the production of pharmaceutical formulations.
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Jacobs M, Lopez CG, Dobrynin AV. Quantifying the Effect of Multivalent Ions in Polyelectrolyte Solutions. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01326] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Michael Jacobs
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Carlos G. Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Aachen 52056, Germany
| | - Andrey V. Dobrynin
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
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Viviani M, Lova P, Portale G. Structural Transitions During Formation and Rehydration of Proton Conducting Polymeric Membranes. Macromol Rapid Commun 2021; 42:e2000717. [PMID: 33998098 DOI: 10.1002/marc.202000717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/17/2021] [Indexed: 11/07/2022]
Abstract
Knowledge of the transitions occurring during the formation of ion-conducting polymer films and membranes is crucial to optimize material performances. The use of non-destructive scattering techniques that offer high spatio-temporal resolution is essential to investigating such structural transitions, especially when combined with complementary techniques probing at different time and spatial scales. Here, a simultaneous multi-technique study is performed on the membrane formation mechanism and the subsequent hydration of two ion-conducting polymers, the well-known commercial Nafion and a synthesized sulfonated poly(phenylene sulfide sulfone) (sPSS). The X-ray data distinguish the multi-stage processes occurring during drying. A sol-gel-membrane transition sequence is observed for both polymers. However, while Nafion membrane evolves from a micellar solution through the formation of a phase-separated gel, forming an oriented supported membrane, sPSS membrane evolves from a solution of dispersed polyelectrolyte chains via formation of an inhomogeneous gel, showing assembly and ionic phase separation only at the end of the drying process. Impedance spectroscopy data confirm the occurrence of the sol-gel transitions, while gel-membrane transitions are detected by optical reflectance data. The simultaneous multi-technique approach presented here can connect the nanoscale to the macroscopic behavior, unraveling information essential to optimize membrane formation of different ion-conducting polymers.
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Affiliation(s)
- Marco Viviani
- Macromolecular Chemistry and New Polymeric Materials, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
| | - Paola Lova
- Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, Genova, 16142, Italy
| | - Giuseppe Portale
- Macromolecular Chemistry and New Polymeric Materials, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
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Gruzinov AY, Schroer MA, Manalastas-Cantos K, Kikhney AG, Hajizadeh NR, Schulz F, Franke D, Svergun DI, Blanchet CE. Anomalous SAXS at P12 beamline EMBL Hamburg: instrumentation and applications. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:812-823. [PMID: 33949989 PMCID: PMC8127372 DOI: 10.1107/s1600577521003404] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 03/30/2021] [Indexed: 05/09/2023]
Abstract
Small-angle X-ray scattering (SAXS) is an established method for studying nanostructured systems and in particular biological macromolecules in solution. To obtain element-specific information about the sample, anomalous SAXS (ASAXS) exploits changes of the scattering properties of selected atoms when the energy of the incident X-rays is close to the binding energy of their electrons. While ASAXS is widely applied to condensed matter and inorganic systems, its use for biological macromolecules is challenging because of the weak anomalous effect. Biological objects are often only available in small quantities and are prone to radiation damage, which makes biological ASAXS measurements very challenging. The BioSAXS beamline P12 operated by the European Molecular Biology Laboratory (EMBL) at the PETRA III storage ring (DESY, Hamburg) is dedicated to studies of weakly scattering objects. Here, recent developments at P12 allowing for ASAXS measurements are presented. The beamline control, data acquisition and data reduction pipeline of the beamline were adapted to conduct ASAXS experiments. Modelling tools were developed to compute ASAXS patterns from atomic models, which can be used to analyze the data and to help designing appropriate data collection strategies. These developments are illustrated with ASAXS experiments on different model systems performed at the P12 beamline.
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Affiliation(s)
- Andrey Yu. Gruzinov
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Martin A. Schroer
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Karen Manalastas-Cantos
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
- Center for Data and Computing in Natural Science, University of Hamburg, Bundesstrasse 43, 20146 Hamburg, Germany
| | - Alexey G. Kikhney
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Nelly R. Hajizadeh
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
- Novartis, Novartis Campus, Fabrikstrasse 2, 4056 Basel, Switzerland
| | - Florian Schulz
- Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Daniel Franke
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Clement E. Blanchet
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
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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] [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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Cruz K, Wang YH, Oake SA, Janmey PA. Polyelectrolyte Gels Formed by Filamentous Biopolymers: Dependence of Crosslinking Efficiency on the Chemical Softness of Divalent Cations. Gels 2021; 7:41. [PMID: 33917686 PMCID: PMC8167600 DOI: 10.3390/gels7020041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 01/21/2023] Open
Abstract
Filamentous anionic polyelectrolytes are common in biological materials. Some examples are the cytoskeletal filaments that assemble into networks and bundled structures to give the cell mechanical resistance and that act as surfaces on which enzymes and other molecules can dock. Some viruses, especially bacteriophages are also long thin polyelectrolytes, and their bending stiffness is similar to those of the intermediate filament class of cytoskeletal polymers. These relatively stiff, thin, and long polyelectrolytes have charge densities similar to those of more flexible polyelectrolytes such as DNA, hyaluronic acid, and polyacrylates, and they can form interpenetrating networks and viscoelastic gels at volume fractions far below those at which more flexible polymers form hydrogels. In this report, we examine how different types of divalent and multivalent counterions interact with two biochemically different but physically similar filamentous polyelectrolytes: Pf1 virus and vimentin intermediate filaments (VIF). Different divalent cations aggregate both polyelectrolytes similarly, but transition metal ions are more efficient than alkaline earth ions and their efficiency increases with increasing atomic weight. Comparison of these two different types of polyelectrolyte filaments enables identification of general effects of counterions with polyelectrolytes and can identify cases where the interaction of the counterions and the filaments exhibits stronger and more specific interactions than those of counterion condensation.
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Affiliation(s)
- Katrina Cruz
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19063, USA; (K.C.); (Y.-H.W.); (S.A.O.)
| | - Yu-Hsiu Wang
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19063, USA; (K.C.); (Y.-H.W.); (S.A.O.)
- Department Biochemistry and Molecular Biology, University of Texas Medical Branch, Rm 6.160, 11th and Mechanic St., Medical Research Building, Galveston, TX 77555, USA
| | - Shaina A. Oake
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19063, USA; (K.C.); (Y.-H.W.); (S.A.O.)
| | - Paul A. Janmey
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19063, USA; (K.C.); (Y.-H.W.); (S.A.O.)
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Horkay F, Chremos A, Douglas JF, L. Jones R, Lou J, Xia Y. Systematic investigation of synthetic polyelectrolyte bottlebrush solutions by neutron and dynamic light scattering, osmometry, and molecular dynamics simulation. J Chem Phys 2020; 152:194904. [PMID: 33687251 PMCID: PMC7252672 DOI: 10.1063/5.0007271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/03/2020] [Indexed: 01/30/2023] Open
Abstract
There is a great interest in the synthesis and characterization of polyelectrolytes that mimic naturally occurring bottlebrush polyelectrolytes to capitalize on the unique properties of this class of macromolecules. Charged bottlebrush polymers form the protective mucus layer in the lungs, stomach, and orifices of animals and provide osmotic stabilization and lubrication to joints. In the present work, we systematically investigate bottlebrush poly(sodium acrylates) through a combination of measurements of solution properties (osmometry, small-angle neutron scattering, and dynamic light scattering) and molecular dynamics simulations, where the bottlebrush properties are compared in each case to their linear polymer counterparts. These complementary experimental and computational methods probe vastly different length- and timescales, allowing for a comprehensive characterization of the supermolecular structure and dynamics of synthetic polyelectrolyte bottlebrush molecules in solution.
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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, Maryland 20892, USA
| | - Alexandros Chremos
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Ronald L. Jones
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Junzhe Lou
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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Sharratt WN, O’Connell R, Rogers SE, Lopez CG, Cabral JT. Conformation and Phase Behavior of Sodium Carboxymethyl Cellulose in the Presence of Mono- and Divalent Salts. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02228] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- William N. Sharratt
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Róisín O’Connell
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Sarah E. Rogers
- ISIS, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, U.K
| | - Carlos G. Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - João T. Cabral
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
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12
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Small-Angle Scattering from Fractals: Differentiating between Various Types of Structures. Symmetry (Basel) 2020. [DOI: 10.3390/sym12010065] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Small-angle scattering (SAS; X-rays, neutrons, light) is being increasingly used to better understand the structure of fractal-based materials and to describe their interaction at nano- and micro-scales. To this aim, several minimalist yet specific theoretical models which exploit the fractal symmetry have been developed to extract additional information from SAS data. Although this problem can be solved exactly for many particular fractal structures, due to the intrinsic limitations of the SAS method, the inverse scattering problem, i.e., determination of the fractal structure from the intensity curve, is ill-posed. However, fractals can be divided into various classes, not necessarily disjointed, with the most common being random, deterministic, mass, surface, pore, fat and multifractals. Each class has its own imprint on the scattering intensity, and although one cannot uniquely identify the structure of a fractal based solely on SAS data, one can differentiate between various classes to which they belong. This has important practical applications in correlating their structural properties with physical ones. The article reviews SAS from several fractal models with an emphasis on describing which information can be extracted from each class, and how this can be performed experimentally. To illustrate this procedure and to validate the theoretical models, numerical simulations based on Monte Carlo methods are performed.
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Sinha NJ, Wu D, Kloxin CJ, Saven JG, Jensen GV, Pochan DJ. Polyelectrolyte character of rigid rod peptide bundlemer chains constructed via hierarchical self-assembly. SOFT MATTER 2019; 15:9858-9870. [PMID: 31738361 DOI: 10.1039/c9sm01894h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Short α-helical peptides were computationally designed to self-assemble into robust coiled coils that are antiparallel, homotetrameric bundles. These peptide bundle units, or 'bundlemers', have been utilized as anisotropic building blocks to construct bundlemer-based polymers via a hierarchical, hybrid physical-covalent assembly pathway. The bundlemer chains were constructed using short linker connections via 'click' chemistry reactions between the N-termini of bundlemer constituent peptides. The resulting bundlemer chains appear as extremely rigid, cylindrical rods in transmission electron microscopy (TEM) images. Small angle neutron scattering (SANS) shows that these bundlemer chains exist as individual rods in solution with a cross-section that is equal to that of a single coiled coil bundlemer building block of ≈20 Å. SANS further confirms that the interparticle solution structure of the rigid rod bundlemer chains is heterogeneous and responsive to solution conditions, such as ionic-strength and pH. Due to their peptidic constitution, the bundlemer assemblies behave like polyelectrolytes that carry an average charge density of approximately 3 charges per bundlemer as determined from SANS structure factor data fitting, which describes the repulsion between charged rods in solution. This repulsion manifests as a correlation hole in the scattering profile that is suppressed by dilution or addition of salt. Presence of rod cluster aggregates with a mass fractal dimension of ≈2.5 is also confirmed across all samples. The formation of such dense, fractal-like cluster aggregates in a solution of net repulsive rods is a unique example of the subtle balance between short-range attraction and long-rage repulsion interactions in proteins and other biomaterials. With computational control of constituent peptide sequences, it is further possible to deconvolute the underlying sequence driven structure-property relationships in the modular bundlemer chains.
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Affiliation(s)
- Nairiti J Sinha
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
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14
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Ryu J, Kim S, Oh I, Kato S, Kosuge T, Sokolova AV, Lee J, Otsuka H, Sohn D. Internal Structure of Hyaluronic Acid Hydrogels Controlled by Iron(III) Ion–Catechol Complexation. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00889] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jungju Ryu
- Department of Chemistry, Research Institute of Natural Sciences, Hanyang University, Seoul 04763, Korea
- Neutron Science Center, Korea Atomic Energy Research Institute, Daejeon 34057, Korea
| | - Sunhye Kim
- Department of Chemistry, Research Institute of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Inwook Oh
- Department of Chemistry, Research Institute of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Sota Kato
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1
Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Takahiro Kosuge
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1
Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Anna V. Sokolova
- Australian Centre for Neutron Scattering, ANSTO, Lucas Heights, New South Wales 2234, Australia
| | - Jeongwook Lee
- Department of Chemistry, Research Institute of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Hideyuki Otsuka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1
Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Daewon Sohn
- Department of Chemistry, Research Institute of Natural Sciences, Hanyang University, Seoul 04763, Korea
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15
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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] [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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