1
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Kelly S, Genevskiy V, Björklund S, Gonzalez-Martinez JF, Poeschke L, Schröder M, Nilius G, Tatkov S, Kocherbitov V. Water Sorption and Structural Properties of Human Airway Mucus in Health and Muco-Obstructive Diseases. Biomacromolecules 2024; 25:1578-1591. [PMID: 38333985 PMCID: PMC10934264 DOI: 10.1021/acs.biomac.3c01170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/25/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024]
Abstract
Muco-obstructive diseases change airway mucus properties, impairing mucociliary transport and increasing the likelihood of infections. To investigate the sorption properties and nanostructures of mucus in health and disease, we investigated mucus samples from patients and cell cultures (cc) from healthy, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) airways. Atomic force microscopy (AFM) revealed mucin monomers with typical barbell structures, where the globule to spacer volume ratio was the highest for CF mucin. Accordingly, synchrotron small-angle X-ray scattering (SAXS) revealed more pronounced scattering from CF mucin globules and suggested shorter carbohydrate side chains in CF mucin and longer side chains in COPD mucin. Quartz crystal microbalance with dissipation (QCM-D) analysis presented water sorption isotherms of the three types of human airway mucus, where, at high relative humidity, COPD mucus had the highest water content compared to cc-CF and healthy airway mucus (HAM). The higher hydration of the COPD mucus is consistent with the observation of longer side chains of the COPD mucins. At low humidity, no dehydration-induced glass transition was observed in healthy and diseased mucus, suggesting mucus remained in a rubbery state. However, in dialyzed cc-HAM, a sorption-desorption hysteresis (typically observed in the glassy state) appeared, suggesting that small molecules present in mucus suppress the glass transition.
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Affiliation(s)
- Susyn
J. Kelly
- Fisher
& Paykel Healthcare Ltd., 15 Maurice Paykel Place, East Tamaki, Auckland NZ-2013, New Zealand
- Department
of Clinical Sciences, Ross University of
Veterinary Medicine, Basseterre KN-0101, Saint
Kitts and Nevis
| | - Vladislav Genevskiy
- Biomedical
Science, Faculty of Health and Society, Malmö University, Malmö SE-20506, Sweden
- Biofilms
Research Center for Biointerfaces, Faculty of Health and Society, Malmö University, Malmö SE-20506, Sweden
| | - Sebastian Björklund
- Biomedical
Science, Faculty of Health and Society, Malmö University, Malmö SE-20506, Sweden
- Biofilms
Research Center for Biointerfaces, Faculty of Health and Society, Malmö University, Malmö SE-20506, Sweden
| | | | - Lara Poeschke
- Evang. Kliniken
Essen-Mitte GmbH, Essen DE-45136, Germany
| | - Maik Schröder
- Evang. Kliniken
Essen-Mitte GmbH, Essen DE-45136, Germany
| | - Georg Nilius
- Evang. Kliniken
Essen-Mitte GmbH, Essen DE-45136, Germany
- Universität
Witten/Herdecke, Witten DE-58455, Germany
| | - Stanislav Tatkov
- Fisher
& Paykel Healthcare Ltd., 15 Maurice Paykel Place, East Tamaki, Auckland NZ-2013, New Zealand
| | - Vitaly Kocherbitov
- Biomedical
Science, Faculty of Health and Society, Malmö University, Malmö SE-20506, Sweden
- Biofilms
Research Center for Biointerfaces, Faculty of Health and Society, Malmö University, Malmö SE-20506, Sweden
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2
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Micheletti C, Chubak I, Orlandini E, Smrek J. Topology-Based Detection and Tracking of Deadlocks Reveal Aging of Active Ring Melts. ACS Macro Lett 2024:124-129. [PMID: 38198592 PMCID: PMC10883035 DOI: 10.1021/acsmacrolett.3c00567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Connecting the viscoelastic behavior of stressed ring melts to the various forms of entanglement that can emerge in such systems is still an open challenge. Here, we consider active ring melts, where stress is generated internally, and introduce a topology-based method to detect and track consequential forms of ring entanglements, namely, deadlocks. We demonstrate that, as stress accumulates, more and more rings are co-opted in a growing web of deadlocks that entrap many other rings by threading, bringing the system to a standstill. The method ought to help the study of topological aging in more general polymer contexts.
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Affiliation(s)
- Cristian Micheletti
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, I-34136 Trieste, Italy
| | - Iurii Chubak
- Sorbonne Université CNRS, Physico-Chimie des électrolytes et Nanosystèmes Interfaciaux, F-75005 Paris, France
| | - Enzo Orlandini
- Università degli studi di Padova, Dipartimento di Fisica "G. Galilei", Via Marzolo 8, I-35100 Padova, Italy
| | - Jan Smrek
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
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3
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Junier I, Ghobadpour E, Espeli O, Everaers R. DNA supercoiling in bacteria: state of play and challenges from a viewpoint of physics based modeling. Front Microbiol 2023; 14:1192831. [PMID: 37965550 PMCID: PMC10642903 DOI: 10.3389/fmicb.2023.1192831] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 09/25/2023] [Indexed: 11/16/2023] Open
Abstract
DNA supercoiling is central to many fundamental processes of living organisms. Its average level along the chromosome and over time reflects the dynamic equilibrium of opposite activities of topoisomerases, which are required to relax mechanical stresses that are inevitably produced during DNA replication and gene transcription. Supercoiling affects all scales of the spatio-temporal organization of bacterial DNA, from the base pair to the large scale chromosome conformation. Highlighted in vitro and in vivo in the 1960s and 1970s, respectively, the first physical models were proposed concomitantly in order to predict the deformation properties of the double helix. About fifteen years later, polymer physics models demonstrated on larger scales the plectonemic nature and the tree-like organization of supercoiled DNA. Since then, many works have tried to establish a better understanding of the multiple structuring and physiological properties of bacterial DNA in thermodynamic equilibrium and far from equilibrium. The purpose of this essay is to address upcoming challenges by thoroughly exploring the relevance, predictive capacity, and limitations of current physical models, with a specific focus on structural properties beyond the scale of the double helix. We discuss more particularly the problem of DNA conformations, the interplay between DNA supercoiling with gene transcription and DNA replication, its role on nucleoid formation and, finally, the problem of scaling up models. Our primary objective is to foster increased collaboration between physicists and biologists. To achieve this, we have reduced the respective jargon to a minimum and we provide some explanatory background material for the two communities.
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Affiliation(s)
- Ivan Junier
- CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Université Grenoble Alpes, Grenoble, France
| | - Elham Ghobadpour
- CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Université Grenoble Alpes, Grenoble, France
- École Normale Supérieure (ENS) de Lyon, CNRS, Laboratoire de Physique and Centre Blaise Pascal de l'ENS de Lyon, Lyon, France
| | - Olivier Espeli
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Ralf Everaers
- École Normale Supérieure (ENS) de Lyon, CNRS, Laboratoire de Physique and Centre Blaise Pascal de l'ENS de Lyon, Lyon, France
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4
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Ubertini MA, Smrek J, Rosa A. Entanglement Length Scale Separates Threading from Branching of Unknotted and Non-concatenated Ring Polymers in Melts. Macromolecules 2022; 55:10723-10736. [PMID: 36530522 PMCID: PMC9753756 DOI: 10.1021/acs.macromol.2c01264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/14/2022] [Indexed: 11/30/2022]
Abstract
Current theories on the conformation and dynamics of unknotted and non-concatenated ring polymers in melt conditions describe each ring as a tree-like double-folded object. While evidence from simulations supports this picture on a single ring level, other works show pairs of rings also thread each other, a feature overlooked in the tree theories. Here we reconcile this dichotomy using Monte Carlo simulations of the ring melts with different bending rigidities. We find that rings are double-folded (more strongly for stiffer rings) on and above the entanglement length scale, while the threadings are localized on smaller scales. The different theories disagree on the details of the tree structure, i.e., the fractal dimension of the backbone of the tree. In the stiffer melts we find an indication of a self-avoiding scaling of the backbone, while more flexible chains do not exhibit such a regime. Moreover, the theories commonly neglect threadings and assign different importance to the impact of the progressive constraint release (tube dilation) on single ring relaxation due to the motion of other rings. Despite that each threading creates only a small opening in the double-folded structure, the threading loops can be numerous and their length can exceed substantially the entanglement scale. We link the threading constraints to the divergence of the relaxation time of a ring, if the tube dilation is hindered by pinning a fraction of other rings in space. Current theories do not predict such divergence and predict faster than measured diffusion of rings, pointing at the relevance of the threading constraints in unpinned systems as well. Revision of the theories with explicit threading constraints might elucidate the validity of the conjectured existence of topological glass.
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Affiliation(s)
- Mattia Alberto Ubertini
- Scuola
Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136Trieste, Italy
| | - Jan Smrek
- Faculty
of Physics, University of Vienna, Boltzmanngasse 5, A-1090Vienna, Austria
| | - Angelo Rosa
- Scuola
Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136Trieste, Italy
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5
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Tubiana L, Ferrari F, Orlandini E. Circular Polycatenanes: Supramolecular Structures with Topologically Tunable Properties. PHYSICAL REVIEW LETTERS 2022; 129:227801. [PMID: 36493458 DOI: 10.1103/physrevlett.129.227801] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 08/11/2022] [Accepted: 10/04/2022] [Indexed: 06/17/2023]
Abstract
Polycatenanes, macrochains of topologically interlocked rings with unique physical properties have recently gained considerable interest in supramolecular chemistry, biology, and soft matter. Most of the work has been, so far, focused on linear chains and on their variety of conformational properties compared to standard polymers. Here we go beyond the linear case and show that, by circularizing such macrochains, one can exploit the topology of the local interlockings to store twist in the system, significantly altering its metric and local properties. Moreover, by properly defining the twist (Tw) and writhe (Wr) of these macrorings we show the validity of a relation equivalent to the Călugăreanu-White-Fuller theorem Tw+Wr=const, originally proved for ribbonlike structures such as double stranded DNA. Our results suggest that circular polycatenanes with storable and tunable twist can form a new category of highly designable multiscale structures with potential applications in supramolecular chemistry and material science.
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Affiliation(s)
- L Tubiana
- Physics Department, University of Trento, via Sommarive, 14 I-38123 Trento, Italy; INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, I-38123 Trento, Italy and Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - F Ferrari
- CASA* and Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland
| | - E Orlandini
- Department of Physics and Astronomy, University of Padova, Via Marzolo 8, I-35131 Padova, Italy and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
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6
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Schmid F. Understanding and Modeling Polymers: The Challenge of Multiple Scales. ACS POLYMERS AU 2022. [DOI: 10.1021/acspolymersau.2c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Friederike Schmid
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 9, 55128Mainz, Germany
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7
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Stars, combs and bottlebrushes of elastic single-chain nanoparticles. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Benderskii VA, Kats EI, Kim IP. Statistical Thermodynamics and Kinetics of Polycondensation: 1. Ensembles with Randomly Arranged Bonds between Monomers. HIGH ENERGY CHEMISTRY 2022. [DOI: 10.1134/s001814392204004x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Tardy BL, Mattos BD, Otoni CG, Beaumont M, Majoinen J, Kämäräinen T, Rojas OJ. Deconstruction and Reassembly of Renewable Polymers and Biocolloids into Next Generation Structured Materials. Chem Rev 2021; 121:14088-14188. [PMID: 34415732 PMCID: PMC8630709 DOI: 10.1021/acs.chemrev.0c01333] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Indexed: 12/12/2022]
Abstract
This review considers the most recent developments in supramolecular and supraparticle structures obtained from natural, renewable biopolymers as well as their disassembly and reassembly into engineered materials. We introduce the main interactions that control bottom-up synthesis and top-down design at different length scales, highlighting the promise of natural biopolymers and associated building blocks. The latter have become main actors in the recent surge of the scientific and patent literature related to the subject. Such developments make prominent use of multicomponent and hierarchical polymeric assemblies and structures that contain polysaccharides (cellulose, chitin, and others), polyphenols (lignins, tannins), and proteins (soy, whey, silk, and other proteins). We offer a comprehensive discussion about the interactions that exist in their native architectures (including multicomponent and composite forms), the chemical modification of polysaccharides and their deconstruction into high axial aspect nanofibers and nanorods. We reflect on the availability and suitability of the latter types of building blocks to enable superstructures and colloidal associations. As far as processing, we describe the most relevant transitions, from the solution to the gel state and the routes that can be used to arrive to consolidated materials with prescribed properties. We highlight the implementation of supramolecular and superstructures in different technological fields that exploit the synergies exhibited by renewable polymers and biocolloids integrated in structured materials.
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Affiliation(s)
- Blaise L. Tardy
- Department
of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
| | - Bruno D. Mattos
- Department
of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
| | - Caio G. Otoni
- Department
of Physical Chemistry, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, São Paulo 13083-970, Brazil
- Department
of Materials Engineering, Federal University
of São Carlos, Rod. Washington Luís, km 235, São
Carlos, São Paulo 13565-905, Brazil
| | - Marco Beaumont
- School
of Chemistry and Physics, Queensland University
of Technology, 2 George
Street, Brisbane, Queensland 4001, Australia
- Department
of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences, Vienna, A-3430 Tulln, Austria
| | - Johanna Majoinen
- Department
of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
| | - Tero Kämäräinen
- Department
of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
| | - Orlando J. Rojas
- Department
of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
- Bioproducts
Institute, Department of Chemical and Biological Engineering, Department
of Chemistry and Department of Wood Science, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
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10
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Ghobadpour E, Kolb M, Ejtehadi MR, Everaers R. Monte Carlo simulation of a lattice model for the dynamics of randomly branching double-folded ring polymers. Phys Rev E 2021; 104:014501. [PMID: 34412203 DOI: 10.1103/physreve.104.014501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 06/07/2021] [Indexed: 11/07/2022]
Abstract
Supercoiled DNA, crumpled interphase chromosomes, and topologically constrained ring polymers often adopt treelike, double-folded, randomly branching configurations. Here we study an elastic lattice model for tightly double-folded ring polymers, which allows for the spontaneous creation and deletion of side branches coupled to a diffusive mass transport, which is local both in space and on the connectivity graph of the tree. We use Monte Carlo simulations to study systems falling into three different universality classes: ideal double-folded rings without excluded volume interactions, self-avoiding double-folded rings, and double-folded rings in the melt state. The observed static properties are in good agreement with exact results, simulations, and predictions of Flory theory for randomly branching polymers. For example, in the melt state rings adopt compact configurations and exhibit territorial behavior. In particular, we show that the emergent dynamics is in excellent agreement with a recent scaling theory and illustrate the qualitative differences with the familiar reptation dynamics of linear chains.
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Affiliation(s)
- Elham Ghobadpour
- Université Grenoble Alpes, Centre National de la Recherche Scientifique (CNRS), TIMC, F-38000 Grenoble, France.,School of Nano Science, Institute for Research in Fundamental Sciences (IPM), 19395-5531, Tehran, Iran
| | - Max Kolb
- Université de Lyon, École Normale Supérieure (ENS) de Lyon, CNRS, Laboratoire de Physique and Centre Blaise Pascal de l'ENS de Lyon, F-69342 Lyon, France
| | | | - Ralf Everaers
- Université de Lyon, École Normale Supérieure (ENS) de Lyon, CNRS, Laboratoire de Physique and Centre Blaise Pascal de l'ENS de Lyon, F-69342 Lyon, France
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11
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Micheletti C, Hauke P, Faccioli P. Polymer Physics by Quantum Computing. PHYSICAL REVIEW LETTERS 2021; 127:080501. [PMID: 34477421 DOI: 10.1103/physrevlett.127.080501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/21/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Sampling equilibrium ensembles of dense polymer mixtures is a paradigmatically hard problem in computational physics, even in lattice-based models. Here, we develop a formalism based on interacting binary tensors that allows for tackling this problem using quantum annealing machines. Our approach is general in that properties such as self-avoidance, branching, and looping can all be specified in terms of quadratic interactions of the tensors. Microstates' realizations of different lattice polymer ensembles are then seamlessly generated by solving suitable discrete energy-minimization problems. This approach enables us to capitalize on the strengths of quantum annealing machines, as we demonstrate by sampling polymer mixtures from low to high densities, using the D-Wave quantum annealer. Our systematic approach offers a promising avenue to harness the rapid development of quantum machines for sampling discrete models of filamentous soft-matter systems.
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Affiliation(s)
- Cristian Micheletti
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, I-34136 Trieste, Italy
| | - Philipp Hauke
- Physics Department of Trento University and INO-CNR BEC Center, Via Sommarive 14, I-38123 Povo (Trento), Italy
| | - Pietro Faccioli
- Physics Department of Trento University and INFN-TIFPA, Via Sommarive 14, I-38123 Povo (Trento), Italy
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12
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Cassin SR, Flynn S, Chambon P, Rannard SP. Quantification of branching within high molecular weight polymers with polyester backbones formed by transfer-dominated branching radical telomerisation (TBRT). RSC Adv 2021; 11:24374-24380. [PMID: 35479039 PMCID: PMC9036642 DOI: 10.1039/d1ra03886a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/28/2021] [Indexed: 12/13/2022] Open
Abstract
New branched polymerisations offer previously inaccessible macromolecules and architectural understanding is important as it provides insight into the branching mechanism and enables the determination of structure-property relationships. Here we present a detailed inverse gated 13C NMR characterisation of materials derived from the very recently reported Transfer-dominated Branching Radical Telomerisation (TBRT) approach to quantify branching and provide an insight into cyclisation.
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Affiliation(s)
- Savannah R Cassin
- Department of Chemistry, University of Liverpool Crown Street L69 7ZD UK
- Materials Innovation Factory, University of Liverpool Crown Street L69 7ZD UK
| | - Sean Flynn
- Department of Chemistry, University of Liverpool Crown Street L69 7ZD UK
- Materials Innovation Factory, University of Liverpool Crown Street L69 7ZD UK
| | - Pierre Chambon
- Department of Chemistry, University of Liverpool Crown Street L69 7ZD UK
- Materials Innovation Factory, University of Liverpool Crown Street L69 7ZD UK
| | - Steve P Rannard
- Department of Chemistry, University of Liverpool Crown Street L69 7ZD UK
- Materials Innovation Factory, University of Liverpool Crown Street L69 7ZD UK
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13
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Kim IP, Kotkin AS, Benderskii VA. Polycondensation Kinetics: 4. Growth of Acyclic Randomly Branched Chains. HIGH ENERGY CHEMISTRY 2021. [DOI: 10.1134/s0018143921030061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Smrek J, Garamella J, Robertson-Anderson R, Michieletto D. Topological tuning of DNA mobility in entangled solutions of supercoiled plasmids. SCIENCE ADVANCES 2021; 7:eabf9260. [PMID: 33980492 PMCID: PMC8115916 DOI: 10.1126/sciadv.abf9260] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 03/26/2021] [Indexed: 05/04/2023]
Abstract
Ring polymers in dense solutions are among the most intriguing problems in polymer physics. Because of its natural occurrence in circular form, DNA has been extensively used as a proxy to study the fundamental physics of ring polymers in different topological states. Yet, torsionally constrained-such as supercoiled-topologies have been largely neglected so far. The applicability of existing theoretical models to dense supercoiled DNA is thus unknown. Here, we address this gap by coupling large-scale molecular dynamics simulations with differential dynamic microscopy of entangled supercoiled DNA plasmids. We find that, unexpectedly, larger supercoiling increases the size of entangled plasmids and concomitantly induces an enhancement in DNA mobility. These findings are reconciled as due to supercoiling-driven asymmetric and double-folded plasmid conformations that reduce interplasmid entanglements and threadings. Our results suggest a way to topologically tune DNA mobility via supercoiling, thus enabling topological control over the (micro)rheology of DNA-based complex fluids.
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Affiliation(s)
- Jan Smrek
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Jonathan Garamella
- Department of Physics and Biophysics, University of San Diego, San Diego, CA 92110, USA
| | | | - Davide Michieletto
- School of Physics and Astronomy, University of Edinburgh Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine University of Edinburgh, Edinburgh EH4 2XU, UK
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15
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Kim IP, Chernyak AV, Benderskii VA. Polycondensation Kinetics: 3. Time-Dependent 29Si NMR Spectra of Poly(methyltrimethoxysilane). HIGH ENERGY CHEMISTRY 2021. [DOI: 10.1134/s0018143921020077] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Spectroscopic Investigation of Chlorin-Based Photosensitizers in Polymer Matrix. INT J POLYM SCI 2021. [DOI: 10.1155/2021/8842052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Chlorin e6 and its derivatives are the basis of a number of drugs used in medicine in the treatment of various diseases, including cancer, by photodynamic therapy. Nonpolar derivatives of Chlorin e6—dimethyl ether of Chlorin e6 (DME Ce6) and trimethyl ether of Chlorin e6 (TME Ce6)—are actively studied for application during photodynamic therapy. In this work, based on the electron optical absorption spectra, the interaction of photosensitizer molecules with branched star-like copolymer dextran-graft-polyacrylamide in anionic form was investigated and the possibility of using the latter as a carrier for drug delivery to tumor cells was suggested.
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17
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Mintis DG, Alexiou TS, Mavrantzas VG. Effect of pH and Molecular Length on the Structure and Dynamics of Linear and Short-Chain Branched Poly(ethylene imine) in Dilute Solution: Scaling Laws from Detailed Molecular Dynamics Simulations. J Phys Chem B 2020; 124:6154-6169. [PMID: 32524817 DOI: 10.1021/acs.jpcb.0c04135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atomistic molecular dynamics (MD) simulations are carried out to examine the effect of molecular weight Mw (= 0.6, 0.86, 1.12, and 2.15 kDa) and pH (or equivalently, degree of ionization, α+ = 0, 50, and 100%) on the structure, state of hydration, and dynamics of linear and branched poly(ethylene imine) (PEI) chains in infinitely dilute salt-free aqueous solutions. It is found that the degree of ionization is the key factor determining the type of molecular conformation adopted by PEI, regardless of molecular architecture and chain length, resulting in a stable trans conformation for fully ionized solutions and in a stable gauche+/gauche- state for neutral or alternate ionized ones; in the latter case, a strong electrolyte behavior is verified for both linear and branched PEI. Linear PEI is observed to be significantly stiffer than branched PEI of the same molecular weight at 100% degree of ionization, but the effect subsides as the degree of ionization decreases. Also, linear PEI diffuses markedly slower than branched PEI of the same Mw. From the MD results, scaling exponents are deduced and reported for the conformation, solvent-accessible surface area, and dynamics of the two different PEI structures with Mw.
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Affiliation(s)
- Dimitris G Mintis
- Department of Chemical Engineering, University of Patras & FORTH-ICE/HT, Patras, GR26504 Greece
| | - Terpsichori S Alexiou
- Department of Chemical Engineering, University of Patras & FORTH-ICE/HT, Patras, GR26504 Greece
| | - Vlasis G Mavrantzas
- Department of Chemical Engineering, University of Patras & FORTH-ICE/HT, Patras, GR26504 Greece.,Department of Mechanical and Process Engineering, Particle Technology Laboratory, ETH Zürich, CH-8092 Zürich, Switzerland
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18
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Deviri D, Safran SA. Equilibrium size distribution and phase separation of multivalent, molecular assemblies in dilute solution. SOFT MATTER 2020; 16:5458-5469. [PMID: 32484171 DOI: 10.1039/c9sm02408e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multivalent molecules can bind a limited number of multiple neighbors via specific interactions. In this paper, we investigate theoretically the self-assembly and phase separation of such molecules in dilute solution. We show that the equilibrium size (n) distributions of linear or branched assemblies qualitatively differ; the former decays exponentially with the relative size n/N[combining macron] (N[combining macron] = n), while the latter decays as a power law, with an exponential cutoff only for n ⪆ N[combining macron]2 ≫ N[combining macron]. In some cases, finite, branched assemblies are unstable and show a sol-gel transition at a critical concentration. In dilute solutions, non-specific interactions result in phase separation, whose critical point is described by an effective Flory Huggins theory that is sensitive to the nature of these distributions.
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Affiliation(s)
- Dan Deviri
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Samuel A Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
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19
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Influence of crowding agents on the dynamics of a multidomain protein in its denatured state: a solvation approach. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:289-305. [PMID: 32399581 DOI: 10.1007/s00249-020-01435-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 03/26/2020] [Accepted: 04/28/2020] [Indexed: 01/01/2023]
Abstract
It is now well appreciated that the crowded intracellular environment significantly modulates an array of physiological processes including protein folding-unfolding, aggregation, and dynamics to name a few. In this work we have studied the dynamics of domain I of the protein human serum albumin (HSA) in its urea-induced denatured states, in the presence of a series of commonly used macromolecular crowding agents. HSA was labeled at Cys-34 (a free cysteine) in domain I with the fluorophore 6-bromoacetyl-2-dimethylaminonaphthalene (BADAN) to act as a solvation probe. In partially denatured states (2-6 M urea), lower crowder concentrations (~ < 125 g/L) induced faster dynamics, while the dynamics became slower beyond 150 g/L of crowders. We propose that this apparent switch in dynamics is an evidence of a crossover from soft (enthalpic) to hard-core (entropic) interactions between the protein and crowder molecules. That soft interactions are also important for the crowders used here was further confirmed by the appreciable shift in the wavelength of the emission maximum of BADAN, in particular for PEG8000 and Ficoll 70 at concentrations where the excluded volume effect is not dominant.
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20
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Proskurina VE, Shilova SV, Kashina ES, Rakhmatullina AP, Galyametdinov YG. Flocculation of Titanium Dioxide with Functionalized Citrus Pectin. RUSS J APPL CHEM+ 2020. [DOI: 10.1134/s107042722002010x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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21
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Adroher-Benítez I, Rosa A. Randomly branching θ-polymers in two and three dimensions: Average properties and distribution functions. J Chem Phys 2020; 152:114903. [DOI: 10.1063/1.5142838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Irene Adroher-Benítez
- SISSA - Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, 34136 Trieste, Italy
| | - Angelo Rosa
- SISSA - Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, 34136 Trieste, Italy
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22
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Hu J, Tang W, Li Y, He J, Guo X, Yang R. The Effect of Glycidyl Azide Polymer Grafted Tetrafunctional Isocyanate on Polytriazole Polyethylene Oxide-Tetrahydrofuran Elastomer and its Propellant Properties. Polymers (Basel) 2020; 12:polym12020278. [PMID: 32023915 PMCID: PMC7077387 DOI: 10.3390/polym12020278] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/28/2019] [Accepted: 01/06/2020] [Indexed: 01/27/2023] Open
Abstract
A new energetic curing reagent, Glycidyl azide polymer grafted tetrafunctional isocyanate (N100-g-GAP) was synthesized and characterized by FT-IR and GPC approaches. Polytriazole polyethylene oxide-tetrahydrofuran (PTPET) elastomer was prepared by N100-g-GAP and alkynyl terminated polyethylene oxide-tetrahydrofuran (ATPET). The resulting PTPET elastomer was fully characterized by TGA, DMA, FTIR and mechanical test. The above analysis indicates that PTPET elastomers using N100-g-GAP as curing reagent have the potential for use in propellants. The overall formulation test of the composite propellants shows that this curing system can effectively enhance mechanical strength and bring a significant improvement in the interface interaction between the RDX & AP particles and binder matrix.
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Affiliation(s)
| | | | | | - Jiyu He
- Correspondence: (J.H.); (X.G.)
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23
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Chremos A, Douglas JF. Influence of Branching on the Configurational and Dynamical Properties of Entangled Polymer Melts. Polymers (Basel) 2019; 11:E1045. [PMID: 31207890 PMCID: PMC6631115 DOI: 10.3390/polym11061045] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/05/2019] [Accepted: 06/06/2019] [Indexed: 11/16/2022] Open
Abstract
We probe the influence of branching on the configurational, packing, and density correlation function properties of polymer melts of linear and star polymers, with emphasis on molecular masses larger than the entanglement molecular mass of linear chains. In particular, we calculate the conformational properties of these polymers, such as the hydrodynamic radius R h , packing length p, pair correlation function g ( r ) , and polymer center of mass self-diffusion coefficient, D, with the use of coarse-grained molecular dynamics simulations. Our simulation results reproduce the phenomenology of simulated linear and branched polymers, and we attempt to understand our observations based on a combination of hydrodynamic and thermodynamic modeling. We introduce a model of "entanglement" phenomenon in high molecular mass polymers that assumes polymers can viewed in a coarse-grained sense as "soft" particles and, correspondingly, we model the emergence of heterogeneous dynamics in polymeric glass-forming liquids to occur in a fashion similar to glass-forming liquids in which the molecules have soft repulsive interactions. Based on this novel perspective of polymer melt dynamics, we propose a functional form for D that can describe our simulation results for both star and linear polymers, covering both the unentangled to entangled polymer melt regimes.
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Affiliation(s)
- Alexandros Chremos
- Materials Science and Engineering Division, 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.
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24
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The Rabl configuration limits topological entanglement of chromosomes in budding yeast. Sci Rep 2019; 9:6795. [PMID: 31043625 PMCID: PMC6494875 DOI: 10.1038/s41598-019-42967-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 03/27/2019] [Indexed: 11/25/2022] Open
Abstract
The three dimensional organization of genomes remains mostly unknown due to their high degree of condensation. Biophysical studies predict that condensation promotes the topological entanglement of chromatin fibers and the inhibition of function. How organisms balance between functionally active genomes and a high degree of condensation remains to be determined. Here we hypothesize that the Rabl configuration, characterized by the attachment of centromeres and telomeres to the nuclear envelope, helps to reduce the topological entanglement of chromosomes. To test this hypothesis we developed a novel method to quantify chromosome entanglement complexity in 3D reconstructions obtained from Chromosome Conformation Capture (CCC) data. Applying this method to published data of the yeast genome, we show that computational models implementing the attachment of telomeres or centromeres alone are not sufficient to obtain the reduced entanglement complexity observed in 3D reconstructions. It is only when the centromeres and telomeres are attached to the nuclear envelope (i.e. the Rabl configuration) that the complexity of entanglement of the genome is comparable to that of the 3D reconstructions. We therefore suggest that the Rabl configuration is an essential player in the simplification of the entanglement of chromatin fibers.
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25
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Polovnikov KE, Nechaev S, Tamm MV. Many-body contacts in fractal polymer chains and fractional Brownian trajectories. Phys Rev E 2019; 99:032501. [PMID: 30999417 DOI: 10.1103/physreve.99.032501] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Indexed: 01/25/2023]
Abstract
We calculate the probabilities that a trajectory of a fractional Brownian motion with arbitrary fractal dimension d_{f} visits the same spot n≥3 times, at given moments t_{1},...,t_{n}, and obtain a determinant expression for these probabilities in terms of a displacement-displacement covariance matrix. Except for the standard Brownian trajectories with d_{f}=2, the resulting many-body contact probabilities cannot be factorized into a product of single-loop contributions. Within a Gaussian network model of a self-interacting polymer chain, which we suggested recently [K. Polovnikov et al., Soft Matter 14, 6561 (2018)1744-683X10.1039/C8SM00785C], the probabilities we calculate here can be interpreted as probabilities of multibody contacts in a fractal polymer conformation with the same fractal dimension d_{f}. This Gaussian approach, which implies a mapping from fractional Brownian motion trajectories to polymer conformations, can be used as a semiquantitative model of polymer chains in topologically stabilized conformations, e.g., in melts of unconcatenated rings or in the chromatin fiber, which is the material medium containing genetic information. The model presented here can be used, therefore, as a benchmark for interpretation of the data of many-body contacts in genomes, which we expect to be available soon in, e.g., Hi-C experiments.
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Affiliation(s)
- K E Polovnikov
- Skolkovo Institute of Science and Technology, 143026 Skolkovo, Russia.,Faculty of Physics, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - S Nechaev
- Interdisciplinary Scientific Center Poncelet (ISCP), 119002, Moscow, Russia.,Lebedev Physical Institute RAS, 119991, Moscow, Russia
| | - M V Tamm
- Faculty of Physics, Lomonosov Moscow State University, 119992 Moscow, Russia.,Department of Applied Mathematics, MIEM, National Research University Higher School of Economics, 101000, Moscow, Russia
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26
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Kelly J, Grosberg AY, Bruinsma R. Generalized Flory Theory for Rotational Symmetry Breaking of Complex Macromolecules. PHYSICAL REVIEW LETTERS 2019; 122:128003. [PMID: 30978098 DOI: 10.1103/physrevlett.122.128003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 06/09/2023]
Abstract
We report on spontaneous rotational symmetry breaking in a minimal model of complex macromolecules with branches and cycles. The transition takes place as the strength of the self-repulsion is increased. At the transition point, the density distribution transforms from isotropic to anisotropic. We analyze this transition using a variational mean-field theory that combines the Gibbs-Bogolyubov-Feynman inequality with the concept of the Laplacian matrix. The density distribution of the broken symmetry state is shown to be determined by the eigenvalues and eigenvectors of this Laplacian matrix. Physically, this reflects the increasing role of the underlying topological structure in determining the density of the macromolecule when repulsive interactions generate internal tension. Eventually, the variational free energy landscape develops a complex structure with multiple competing minima.
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Affiliation(s)
- Josh Kelly
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Alexander Y Grosberg
- Department of Physics and Center for Soft Matter Research, New York University, 726 Broadway, New York, New York 10003, USA
| | - Robijn Bruinsma
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
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27
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Vargas-Lara F, Pazmiño Betancourt BA, Douglas JF. Influence of knot complexity on glass-formation in low molecular mass ring polymer melts. J Chem Phys 2019; 150:101103. [PMID: 30876350 PMCID: PMC11005110 DOI: 10.1063/1.5085425] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We perform molecular dynamics simulations on a coarse-grained polymer melt to study the dynamics of glass-formation in ring polymer melts of variable knot complexity. After generating melts of non-concatenated polymeric rings having a range of minimum crossing number values, mc, we compute the coherent intermediate scattering function, the segmental α-relaxation time, fragility, and the glass transition temperature as a function of mc. Variation of knot complexity is found to have a pronounced effect on the dynamics of polymer melts since both molecular rigidity and packing are altered, primary physical factors governing glass-formation in polymeric materials.
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Affiliation(s)
- Fernando Vargas-Lara
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Beatriz A Pazmiño Betancourt
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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28
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Schram RD, Rosa A, Everaers R. Local loop opening in untangled ring polymer melts: a detailed "Feynman test" of models for the large scale structure. SOFT MATTER 2019; 15:2418-2429. [PMID: 30778466 DOI: 10.1039/c8sm02587h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The conformational statistics of ring polymers in melts or dense solutions is strongly affected by their quenched microscopic topological state. The effect is particularly strong for untangled (i.e. non-concatenated and unknotted) rings, which are known to crumple and segregate. Here we study these systems using a computationally efficient multi-scale approach, where we combine massive simulations on the fiber level with the explicit construction of untangled ring melt configurations based on theoretical ideas for their large scale structure. We find (i) that topological constraints may be neglected on scales below the standard entanglement length, Le, (ii) that rings with a size 1 ≤ Lr/Le ≤ 30 exhibit nearly ideal lattice tree behavior characterized by primitive paths which are randomly branched on the entanglement scale, and (iii) that larger rings are compact with gyration radii Rg2(Lr) ∝ Lr2/3. The detailed comparison between equilibrated and constructed ensembles allows us to perform a "Feynman test" of our understanding of untangled rings: can we convert ideas for the large scale ring structure into algorithms for constructing (nearly) equilibrated ring melt samples? We show that most structural observables are quantitatively reproduced by two different construction schemes: hierarchical crumpling and ring melts derived from the analogy to interacting branched polymers. However, the latter fail the "Feynman test" with respect to the magnetic radius, Rm, which we have defined based on an analogy to magnetostatics. While Rm is expected to vanish for double-folded structures, the observed values of Rm2(Lr) ∝ Rg2(Lr) provide a simple and computationally convenient measure of the presence of a non-negligible amount of local loop opening in crumpled rings.
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Affiliation(s)
- Raoul D Schram
- Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique and Centre Blaise Pascal, F-69342 Lyon, France.
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29
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Rosa A, Everaers R. Conformational statistics of randomly branching double-folded ring polymers. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:7. [PMID: 30659391 DOI: 10.1140/epje/i2019-11765-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/13/2018] [Indexed: 06/09/2023]
Abstract
The conformations of topologically constrained double-folded ring polymers can be described as wrappings of randomly branched primitive trees. We extend previous work on the tree statistics under different (solvent) conditions to explore the conformational statistics of double-folded rings in the limit of tight wrapping. In particular, we relate the exponents characterizing the ring statistics to those describing the primitive trees and discuss the distribution functions [Formula: see text] and [Formula: see text] for the spatial distance, [Formula: see text], and tree contour distance, L, between monomers as a function of their ring contour distance, [Formula: see text].
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Affiliation(s)
- Angelo Rosa
- Sissa (Scuola Internazionale Superiore di Studi Avanzati), Via Bonomea 265, 34136, Trieste, Italy.
| | - Ralf Everaers
- Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique and Centre Blaise Pascal, F-69342, Lyon, France
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30
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Papale A, Rosa A. The Ising model in swollen vs. compact polymers: Mean-field approach and computer simulations. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:144. [PMID: 30552518 DOI: 10.1140/epje/i2018-11752-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
We study the properties of the classical Ising model with nearest-neighbor interaction for spins located at the monomers of long polymer chains in 2 and 3 dimensions. We compare results for two ensembles of polymers with very different single chain properties: 1) swollen, self-avoiding linear polymer chains in good solvent conditions and 2) compact, space-filling randomly branching polymers in melt. By employing a mean-field approach and Monte Carlo computer simulations, we show that swollen polymers cannot sustain an ordered phase. On the contrary, compact polymers may indeed produce an observable phase transition. Finally, we briefly consider the statistical properties of the ordered phase by comparing polymer chains within the same universality class but characterized by very different shapes.
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Affiliation(s)
- Andrea Papale
- Sissa (Scuola Internazionale Superiore di Studi Avanzati), Via Bonomea 265, 34136, Trieste, Italy
| | - Angelo Rosa
- Sissa (Scuola Internazionale Superiore di Studi Avanzati), Via Bonomea 265, 34136, Trieste, Italy.
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31
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Polovnikov K, Nechaev S, Tamm MV. Effective Hamiltonian of topologically stabilized polymer states. SOFT MATTER 2018; 14:6561-6570. [PMID: 30052258 DOI: 10.1039/c8sm00785c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Topologically stabilized polymer conformations in melts of nonconcatenated polymer rings and crumpled globules are considered to be a good candidate for the description of the spatial structure of mitotic chromosomes. Despite significant efforts, the microscopic Hamiltonian capable of describing such systems still remains unknown. We describe a polymer conformation by a Gaussian network - a system with a Hamiltonian quadratic in all coordinates - and show that by tuning interaction constants, one can obtain equilibrium conformations with any fractal dimension between 2 (an ideal polymer chain) and 3 (a crumpled globule). Monomer-to-monomer distances in topologically stabilized states, according to available numerical data, fit very well the Gaussian distribution, giving an additional argument in support of the quadratic Hamiltonian model. Mathematically, the polymer conformations are mapped onto the trajectories of a subdiffusive fractal Brownian particle. Moreover, we explicitly show that the quadratic Hamiltonian with a hierarchical set of coupling constants provides the microscopic background for the description of the path integral of the fractional Brownian motion with an algebraically decaying kernel.
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Affiliation(s)
- K Polovnikov
- Skolkovo Institute of Science and Technology, 143026 Skolkovo, Russia
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32
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Chremos A, Douglas JF. A comparative study of thermodynamic, conformational, and structural properties of bottlebrush with star and ring polymer melts. J Chem Phys 2018; 149:044904. [PMID: 30068167 PMCID: PMC11446256 DOI: 10.1063/1.5034794] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Thermodynamic, conformational, and structural properties of bottlebrush polymer melts are investigated with molecular dynamics simulations and compared to linear, regular star, and unknotted ring polymer melts to gauge the influence of molecular topology on polymer melt properties. We focus on the variation of the backbone chain length, the grafting density along the backbone, and the length of the side chains at different temperatures above the melt glass transition temperature. Based on these comparisons, we find that the segmental density, isothermal compressibility, and isobaric thermal expansion of bottlebrush melts are quantitatively similar to unknotted ring polymer melts and star polymer melts having a moderate number ( f = 5 to 6) of arms. These similarities extend to the mass scaling of the chain radius of gyration. Our results together indicate that the configurational properties of bottlebrush polymers in their melt state are more similar to randomly branched polymers than linear polymer chains. We also find that the average shape of bottlebrush polymers having short backbone chains with respect to the side chain length is also rather similar to the unknotted ring and moderately branched star polymers in their melt state. As a general trend, the molecular shape of bottlebrush polymers becomes more spherically symmetric when the length of the side chains has a commensurate length as the backbone chain. Finally, we calculate the partial static structure factor of the backbone segments and we find the emergence of a peak at the length scales that characterizes the average distance between the backbone chains. This peak is absent when we calculate the full static structure factor. We characterize the scaling of this peak with parameters characterizing the bottlebrush molecular architecture to aid in the experimental characterization of these molecules by neutron scattering.
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Affiliation(s)
- Alexandros Chremos
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD
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33
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Johner A, Lee NK. The Daoud and Cotton blob model and the interaction of star-shaped polymers. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:88. [PMID: 30039228 DOI: 10.1140/epje/i2018-11698-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/02/2018] [Indexed: 06/08/2023]
Abstract
Since it was first proposed in 1982, the Daoud and Cotton (DC) model for star-shaped polymers was intensively used also for self-assembled copolymers and small colloids grafted with long polymers. We try to clarify the position of the DC model and focus on the star partition function which plays a central role in self-assembly and gives access to the star-star interaction. While the predicted star-star interaction agrees with scattering data by Likos et al. (Phys. Rev. Lett. 80, 4450 (1998)), an extensive simulation by Hsu et al. (Macromolecules, 37, 4658 (2004)) does not recover the prediction for the partition function. We try to reconcile this seemingly conflicting results. We discuss star-star interactions, star free energy in θ -solvents, mixing of A/B branches in copolymer stars, within or beyond the Daoud and Cotton blob model.
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Affiliation(s)
- Albert Johner
- Institut Charles Sadron CNRS, Université de Strasbourg, Rue du Loess, 67034, Strasbourg Cedex 2, France.
| | - Nam-Kyung Lee
- Department of Physics, Sejong University, 05006, Seoul, South Korea
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34
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Grosberg AY, Bruinsma R. Confining annealed branched polymers inside spherical capsids. J Biol Phys 2018; 44:133-145. [PMID: 29442192 PMCID: PMC5928018 DOI: 10.1007/s10867-018-9483-x] [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: 11/28/2017] [Accepted: 01/19/2018] [Indexed: 10/18/2022] Open
Abstract
The Lifshitz equation for the confinement of a linear polymer in a spherical cavity of radius R has the form of the Schrödinger equation for a quantum particle trapped in a potential well with flat bottom and infinite walls at radius R. We show that the Lifshitz equation of a confined annealed branched polymer has the form of the Schrödinger equation for a quantum harmonic oscillator. The resulting confinement energy has a 1/R4 dependence on the confinement radius R, in contrast to the case of confined linear polymers, which have a 1/R2 dependence. We discuss the application of this result to the problem of the confinement of single-stranded RNA molecules inside spherical capsids.
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Affiliation(s)
- Alexander Y Grosberg
- Department of Physics and Center for Soft Matter Research, New York University, 726 Broadway, New York, NY, 10003, USA.
| | - Robijn Bruinsma
- Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
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35
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New hybrid composites for photodynamic therapy: synthesis, characterization and biological study. APPLIED NANOSCIENCE 2018. [DOI: 10.1007/s13204-018-0768-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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36
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Shireen Z, Babu SB. Lattice animals in diffusion limited binary colloidal system. J Chem Phys 2017; 147:054904. [PMID: 28789541 DOI: 10.1063/1.4996739] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In a soft matter system, controlling the structure of the amorphous materials has been a key challenge. In this work, we have modeled irreversible diffusion limited cluster aggregation of binary colloids, which serves as a model for chemical gels. Irreversible aggregation of binary colloidal particles leads to the formation of a percolating cluster of one species or both species which are also called bigels. Before the formation of the percolating cluster, the system forms a self-similar structure defined by a fractal dimension. For a one component system when the volume fraction is very small, the clusters are far apart from each other and the system has a fractal dimension of 1.8. Contrary to this, we will show that for the binary system, we observe the presence of lattice animals which has a fractal dimension of 2 irrespective of the volume fraction. When the clusters start inter-penetrating, we observe a fractal dimension of 2.5, which is the same as in the case of the one component system. We were also able to predict the formation of bigels using a simple inequality relation. We have also shown that the growth of clusters follows the kinetic equations introduced by Smoluchowski for diffusion limited cluster aggregation. We will also show that the chemical distance of a cluster in the flocculation regime will follow the same scaling law as predicted for the lattice animals. Further, we will also show that irreversible binary aggregation comes under the universality class of the percolation theory.
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Affiliation(s)
- Zakiya Shireen
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sujin B Babu
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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37
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Dolgushev M, Wittmer JP, Johner A, Benzerara O, Meyer H, Baschnagel J. Marginally compact hyperbranched polymer trees. SOFT MATTER 2017; 13:2499-2512. [PMID: 28304066 DOI: 10.1039/c7sm00243b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Assuming Gaussian chain statistics along the chain contour, we generate by means of a proper fractal generator hyperbranched polymer trees which are marginally compact. Static and dynamical properties, such as the radial intrachain pair density distribution ρpair(r) or the shear-stress relaxation modulus G(t), are investigated theoretically and by means of computer simulations. We emphasize that albeit the self-contact density diverges logarithmically with the total mass N, this effect becomes rapidly irrelevant with increasing spacer length S. In addition to this it is seen that the standard Rouse analysis must necessarily become inappropriate for compact objects for which the relaxation time τp of mode p must scale as τp ∼ (N/p)5/3 rather than the usual square power law for linear chains.
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Affiliation(s)
- M Dolgushev
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany and Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Strasbourg Cedex, France.
| | - J P Wittmer
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Strasbourg Cedex, France.
| | - A Johner
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Strasbourg Cedex, France.
| | - O Benzerara
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Strasbourg Cedex, France.
| | - H Meyer
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Strasbourg Cedex, France.
| | - J Baschnagel
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Strasbourg Cedex, France.
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