1
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Villanueva Valencia JR, Li D, Casjens SR, Evilevitch A. 'SAXS-osmometer' method provides measurement of DNA pressure in viral capsids and delivers an empirical equation of state. Nucleic Acids Res 2023; 51:11415-11427. [PMID: 37889048 PMCID: PMC10681747 DOI: 10.1093/nar/gkad852] [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: 05/16/2023] [Revised: 09/21/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
We present a novel method that provides a measurement of DNA pressure in viral capsids using small angle X-ray scattering (SAXS). This method, unlike our previous assay, does not require triggering genome release with a viral receptor. Thus, it can be used to determine the existence of a pressurized genome state in a wide range of virus systems, even if the receptor is not known, leading to a better understanding of the processes of viral genome uncoating and encapsidation in the course of infection. Furthermore, by measuring DNA pressure for a collection of bacteriophages with varying DNA packing densities, we derived an empirical equation of state (EOS) that accurately predicts the relation between the capsid pressure and the packaged DNA density and includes the contribution of both DNA-DNA interaction energy and DNA bending stress to the total DNA pressure. We believe that our SAXS-osmometer method and the EOS, combined, provide the necessary tools to investigate physico-chemical properties of confined DNA condensates and mechanisms of infection, and may also provide essential data for the design of viral vectors in gene therapy applications and development of antivirals that target the pressurized genome state.
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Affiliation(s)
| | - Dong Li
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Sherwood R Casjens
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Alex Evilevitch
- Department of Experimental Medical Science and NanoLund, Lund University, Box 124, Lund, Sweden
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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2
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Villanueva Valencia JR, Tsimtsirakis E, Krueger S, Evilevitch A. Temperature-induced DNA density transition in phage λ capsid revealed with contrast-matching SANS. Proc Natl Acad Sci U S A 2023; 120:e2220518120. [PMID: 37903276 PMCID: PMC10636372 DOI: 10.1073/pnas.2220518120] [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: 12/04/2022] [Accepted: 09/25/2023] [Indexed: 11/01/2023] Open
Abstract
Structural details of a genome packaged in a viral capsid are essential for understanding how the structural arrangement of a viral genome in a capsid controls its release dynamics during infection, which critically affects viral replication. We previously found a temperature-induced, solid-like to fluid-like mechanical transition of packaged λ-genome that leads to rapid DNA ejection. However, an understanding of the structural origin of this transition was lacking. Here, we use small-angle neutron scattering (SANS) to reveal the scattering form factor of dsDNA packaged in phage λ capsid by contrast matching the scattering signal from the viral capsid with deuterated buffer. We used small-angle X-ray scattering and cryoelectron microscopy reconstructions to determine the initial structural input parameters for intracapsid DNA, which allows accurate modeling of our SANS data. As result, we show a temperature-dependent density transition of intracapsid DNA occurring between two coexisting phases-a hexagonally ordered high-density DNA phase in the capsid periphery and a low-density, less-ordered DNA phase in the core. As the temperature is increased from 20 °C to 40 °C, we found that the core-DNA phase undergoes a density and volume transition close to the physiological temperature of infection (~37 °C). The transition yields a lower energy state of DNA in the capsid core due to lower density and reduced packing defects. This increases DNA mobility, which is required to initiate rapid genome ejection from the virus capsid into a host cell, causing infection. These data reconcile our earlier findings of mechanical DNA transition in phage.
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Affiliation(s)
| | - Efthymios Tsimtsirakis
- Department of Experimental Medical Science and NanoLund, Lund University, Lund22184, Sweden
| | - Susan Krueger
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD20899-6102
| | - Alex Evilevitch
- Department of Experimental Medical Science and NanoLund, Lund University, Lund22184, Sweden
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3
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Abstract
A novel composite hydrogel was developed that shows remarkable similarities to load bearing biological tissues. The composite gel consisting of a poly(vinyl alcohol (PVA) matrix filled with poly(acrylic acid) (PAA) microgel particles exhibits osmotic and mechanical properties that are qualitatively different from regular gels. In the PVA/PAA system the swollen PAA particles "inflate" the PVA network. The swelling of the PAA is limited by the tensile stress Pel developing in the PVA matrix. Pel increases with increasing swelling degree, which is opposite to the decrease of the elastic pressure observed in regular gels. The maximum tensile stress Pmaxel can be identified as a quantity that defines the load bearing ability of the composite gel. Systematic osmotic swelling pressure measurements have been made on PVA/PAA gels to determine the effects of PVA stiffness, PAA crosslink density, and Ca2+ ion concentration on Pmaxel. It is found that Pmaxel increases with the stiffness of the PVA matrix, and decreases with (i) increasing crosslink density of the PAA and (ii) increasing Ca2+ ion concentration. Small angle neutron scattering (SANS) measurements indicate only a weak interaction between the PVA and PAA gels. It is demonstrated that the osmotic swelling pressure of PVA/PAA composite gels reproduces the osmotic behavior of healthy and osteoarthritic cartilage.
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Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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4
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Danielsen SPO, Thompson BJ, Fredrickson GH, Nguyen TQ, Bazan GC, Segalman RA. Ionic Tunability of Conjugated Polyelectrolyte Solutions. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00178] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Scott P. O. Danielsen
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Brittany J. Thompson
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
- School of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
| | - Glenn H. Fredrickson
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Materials Department, University of California, Santa Barbara, California 93106, United States
| | - Thuc-Quyen Nguyen
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Guillermo C. Bazan
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Materials Department, University of California, Santa Barbara, California 93106, United States
- Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Rachel A. Segalman
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Materials Department, University of California, Santa Barbara, California 93106, United States
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5
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Wong LN, Jones SD, Wood K, de Campo L, Darwish T, Moir M, Li H, Segalman RA, Warr GG, Atkin R. Polycation radius of gyration in a polymeric ionic liquid (PIL): the PIL melt is not a theta solvent. Phys Chem Chem Phys 2022; 24:4526-4532. [PMID: 35119064 DOI: 10.1039/d1cp05354j] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conformation of the polycation in the prototypical polymeric ionic liquid (PIL) poly(3-methyl-1-aminopropylimidazolylacrylamide) bis(trifluoromethylsulfonyl)imide (poly(3MAPIm)TFSI) was probed using small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) at 25 °C and 80 °C. Poly(3MAPIm)TFSI contains microvoids which lead to intense low q scattering that can be mitigated using mixtures of hydrogen- and deuterium-rich materials, allowing determination of the polycation conformation and radius of gyration (Rg). In the pure PIL, the polycation adopts a random coil conformation with Rg = 52 ± 0.5 Å. In contrast to conventional polymer melts, the pure PIL is not a theta solvent for the polycation. The TFSI- anions, which comprise 48% v/v of the PIL, are strongly attracted to the polycation and act like small solvent molecules which leads to chain swelling analogous to an entangled, semi-dilute, or concentrated polymer solution in a good solvent.
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Affiliation(s)
- Lucas N Wong
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia.
| | - Seamus D Jones
- Chemical Engineering Department and Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Kathleen Wood
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Liliana de Campo
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Tamim Darwish
- National Deuteration Facility (NDF), ANSTO, Lucas Heights, NSW 2234, Australia
| | - Michael Moir
- National Deuteration Facility (NDF), ANSTO, Lucas Heights, NSW 2234, Australia
| | - Hua Li
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia.
| | - Rachel A Segalman
- Chemical Engineering Department and Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia.
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6
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Mansel BW, Irani AH, Ryan TM, McGillivray DJ, Chen HL, Williams MAK. Resolving solution conformations of the model semi-flexible polyelectrolyte homogalacturonan using molecular dynamics simulations and small-angle x-ray scattering. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:19. [PMID: 30788674 DOI: 10.1140/epje/i2019-11776-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 01/04/2019] [Indexed: 05/27/2023]
Abstract
The conformation of polyelectrolytes in the solution state has long been of interest in polymer science. Herein we utilize all atom molecular dynamics simulations (MD) and small-angle x-ray scattering experiments (SAXS) to elucidate the molecular structure of the model polyelectrolyte homogalacturonan. Several degrees of polymerization were studied and in addition partial methylesterification of the otherwise charge-carrying carboxyl groups was used in order to generate samples with varying intra-chain charge distributions. It is shown that at length scales above around 1nm the conformation of isolated chains has surprisingly little dependence on the charge distribution or the concentration of attendant monovalent salts, reflective of the intrinsic stiffness of the saccharide rings and the dynamical constraints of the glycosidic linkage. Indeed the conformation of isolated chains over all accessible length scales is well described by the atomic coordinates available from fibre diffraction studies. Furthermore, in more concentrated systems it is shown that, after careful analysis of the SAXS data, the form of the inter-particle effects heralded by the emergence of a so-called polyelectrolyte peak, can be extracted, and that this phenomena can be reproduced by multiple chain MD simulations.
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Affiliation(s)
- Bradley W Mansel
- Department of Chemical Engineering, National Tsing Hua University, 30013, Hsinchu, Taiwan.
| | - Amir Hossein Irani
- Institute of Fundamental Sciences, Massey University, 4474, Palmerston North, New Zealand
| | | | - Duncan J McGillivray
- School of Chemical Sciences, University of Auckland, Private Bag 90219, Auckland, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140, Wellington, New Zealand
| | - Hsin-Lung Chen
- Department of Chemical Engineering, National Tsing Hua University, 30013, Hsinchu, Taiwan
| | - Martin A K Williams
- Institute of Fundamental Sciences, Massey University, 4474, Palmerston North, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140, Wellington, New Zealand
- Riddet Institute, Massey University, 4474, Palmerston North, New Zealand
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7
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Hendler N, Wildeman J, Mentovich ED, Schnitzler T, Belgorodsky B, Prusty DK, Rimmerman D, Herrmann A, Richter S. Efficient Separation of Conjugated Polymers Using a Water Soluble Glycoprotein Matrix: From Fluorescence Materials to Light Emitting Devices. Macromol Biosci 2013; 14:320-6. [DOI: 10.1002/mabi.201300329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/29/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Netta Hendler
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
- University Center for Nanoscience and Nanotechnology; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
| | - Jurjen Wildeman
- Department of Polymer Chemistry; University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4; 9747 AG Groningen The Netherlands
| | - Elad. D. Mentovich
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
- University Center for Nanoscience and Nanotechnology; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
| | - Tobias Schnitzler
- Department of Polymer Chemistry; University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4; 9747 AG Groningen The Netherlands
| | - Bogdan Belgorodsky
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
| | - Deepak K. Prusty
- Department of Polymer Chemistry; University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4; 9747 AG Groningen The Netherlands
| | - Dolev Rimmerman
- University Center for Nanoscience and Nanotechnology; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
| | - Andreas Herrmann
- Department of Polymer Chemistry; University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4; 9747 AG Groningen The Netherlands
| | - Shachar Richter
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
- University Center for Nanoscience and Nanotechnology; Tel Aviv University; Ramat Aviv Tel Aviv 69998 Israel
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8
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Manning GS. Counterion condensation theory of attraction between like charges in the absence of multivalent counterions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2011; 34:1-18. [PMID: 22197905 DOI: 10.1140/epje/i2011-11132-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 12/07/2011] [Indexed: 05/31/2023]
Abstract
There is abundant experimental evidence suggesting the existence of attractive interactions among identically charged polyelectrolytes in ordinary salt solutions. The presence of multivalent counterions is not required. We review the relevant literature in detail and conclude that it merits more attention than it has received. We discuss also some recent observations of a low ionic strength attraction of negatively charged DNA to the region of a negatively charged glass nanoslit where the floor of the nanoslit meets the walls, again in the absence of multivalent ions. On the theoretical side, it has become clear that purely electrostatic interactions require the presence of multivalent counterions if they are to generate like-charge attraction. Any theory of like-charge attraction in the absence of multivalent counterions must therefore contain a non-electrostatic component. We point out that counterion condensation theory, which has predicted like-charge polyelectrolyte attraction in an intermediate range of distances in ordinary 1:1 salt conditions, contains both electrostatic and non-electrostatic elements. The non-electrostatic component of the theory is the modeling constraint that the counterions fall into two explicit populations, condensed and uncondensed. As reviewed in the paper, this physically motivated constraint is supported by strong experimental evidence. We proceed to offer an explanation of the nanoslit observations by showing in an idealized model that the line of intersection of two intersecting planes is a virtual polyelectrolyte. Since we have previously developed a counterion condensation theory of attraction of two like-charged polyelectrolytes, our suggestion is that the DNA is attracted to the virtual polyelectrolytes that may be located in the nanoslit where floor meets walls. We present the detailed calculations needed to document this suggestion: an extension of previous theory to the case of polyelectrolytes with like but not identical charges; the demonstration of counterion condensation on a plane with bare charge density greater than an explicitly exhibited critical value; a calculation of the free energy of the plane; a calculation of the interaction of a line charge polyelectrolyte with a like-charged plane; and the detailed demonstration that the line of intersection of two planes is a virtual polyelectrolyte.
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Affiliation(s)
- G S Manning
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8087, USA.
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9
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Xu Z, Tsai H, Wang HL, Cotlet M. Solvent polarity effect on chain conformation, film morphology, and optical properties of a water-soluble conjugated polymer. J Phys Chem B 2011; 114:11746-52. [PMID: 20726542 DOI: 10.1021/jp105032y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The solvent polarity effect on chain conformation, film morphology, and photophysical properties of a nonionic water-soluble conjugated polymer (WSCP), poly[2,5-bis(diethylaminetetraethylene glycol)phenylene vinylene] (DEATG-PPV) is investigated in detail. The combination of stationary absorption and photoluminescence (PL) spectroscopy, time-resolved PL spectroscopy, and fluorescence correlation spectroscopy methods enables us to probe the chain conformation of DEATG-PPV, down to the level of a single chain when working with extremely diluted solutions. The use of correlated atomic force microscopy and confocal fluorescence lifetime imaging microscopy measurements of drop-casted DEATG-PPV films reveals the intrinsic relationship between chain conformation, film morphology, and optical properties. Depending on solvent polarity, DEATG-PPV presents extended, coiled, and collapsed chain conformations in solutions, which lead to distinct morphology and optical properties in solid films. Our work presents a pathway to control and characterize the film morphologies of WSCPs toward the optimal performance of various optoelectronic devices.
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Affiliation(s)
- Zhihua Xu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
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10
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Gutacker A, Adamczyk S, Helfer A, Garner LE, Evans RC, Fonseca SM, Knaapila M, Bazan GC, Burrows HD, Scherf U. All-conjugated polyelectrolyteblock copolymers. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b918583f] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Horkay F, Basser PJ. Ionic and pH effects on the osmotic properties and structure of polyelectrolyte gels. ACTA ACUST UNITED AC 2008; 46:2803-2810. [PMID: 20016687 DOI: 10.1002/polb.21590] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We investigate the effects of salt concentration and pH on neutralized poly(acrylic acid) (PAA) gels in near physiological salt solutions. Either adding calcium ions or decreasing the pH are found to induce reversible volume transitions but the nature of these transitions seems to be different. For example, the osmotic pressure exhibits a simple power law dependence on the concentration as the transition is approached in both systems, but the power law exponent n is substantially different in the two cases. On decreasing the pH the value of n gradually increases from 2.1 (at pH = 7) to 3.2 (at pH = 1). By contrast, n decreases with increasing calcium ion concentration from 2.1 (in 100 mM NaCl solution) to 1.6 (0.8 mM CaCl(2) in 100 mM NaCl solution). In both systems, a strong increase of the small-angle neutron scattering intensity (SANS) is observed near the volume transition. The SANS results reveal that calcium ions favor the formation of linearly aligned regions in PAA gels.
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Affiliation(s)
- Ferenc Horkay
- Section on Tissue Biophysics and Biomimetics, Laboratory of Integrative and Medical Biophysics, NICHD, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA
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12
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Schmit JD, Levine AJ. Statistical model for intermolecular adhesion in pi-conjugated polymers. PHYSICAL REVIEW LETTERS 2008; 100:198303. [PMID: 18518495 DOI: 10.1103/physrevlett.100.198303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 09/10/2007] [Indexed: 05/26/2023]
Abstract
We propose an interchain binding mechanism in pi-conjugated polymers based on the intermolecular tunneling of the delocalized electrons occurring at points where the polymers cross. This mechanism predicts specific bound structures of chains that depend on whether they are semiconducting or metallic. Semiconducting chains should form polyacenelike states exhibiting binding at every other site, while (doped) metallic chains can bind at each site. We also show that solitons colocalize with the intermolecular binding sites thereby strengthening the binding effect and investigate the conformational statistics of the resulting bimolecular aggregates.
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Affiliation(s)
- Jeremy D Schmit
- Materials Research Laboratory, University of California, Santa Barbara, CA 93106, USA
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13
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Vallat P, Catala JM, Rawiso M, Schosseler F. Flexible Conjugated Polyelectrolyte Solutions: A Small Angle Scattering Study. Macromolecules 2007. [DOI: 10.1021/ma062942f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- P. Vallat
- Institut Charles Sadron, 6 rue Boussingault, 67083 Strasbourg Cedex, France
| | - J.-M. Catala
- Institut Charles Sadron, 6 rue Boussingault, 67083 Strasbourg Cedex, France
| | - M. Rawiso
- Institut Charles Sadron, 6 rue Boussingault, 67083 Strasbourg Cedex, France
| | - F. Schosseler
- Institut Charles Sadron, 6 rue Boussingault, 67083 Strasbourg Cedex, France
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14
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Thomas SW, Joly GD, Swager TM. Chemical Sensors Based on Amplifying Fluorescent Conjugated Polymers. Chem Rev 2007; 107:1339-86. [PMID: 17385926 DOI: 10.1021/cr0501339] [Citation(s) in RCA: 2936] [Impact Index Per Article: 172.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Samuel W Thomas
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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15
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Smith AD, Shen CKF, Roberts ST, Helgeson R, Schwartz BJ. Ionic strength and solvent control over the physical structure, electronic properties and superquenching of conjugated polyelectrolytes. RESEARCH ON CHEMICAL INTERMEDIATES 2007. [DOI: 10.1163/156856707779160762] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Fakis M, Anestopoulos D, Giannetas V, Persephonis P, Mikroyannidis J. Femtosecond Time Resolved Fluorescence Dynamics of a Cationic Water-Soluble Poly(fluorenevinylene-co-phenylenevinylene). J Phys Chem B 2006; 110:12926-31. [PMID: 16805593 DOI: 10.1021/jp056385v] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A recently synthesized cationic water-soluble poly(fluorenevinylene-co-phenylenevinylene) was studied by means of steady state and femtosecond time resolved upconversion spectroscopy in aqueous and EtOH solutions. Steady state spectroscopic measurements showed that the polymer emits at the blue-green spectral region and that aggregates are formed in concentrated polymer solutions. The fluorescence dynamics of the polymer in concentrated solutions, studied at a range of emission wavelengths, exhibited a wavelength dependent and multiexponential decay, indicating the existence of various decay mechanisms. Specifically, a rapid decay at short emission wavelengths and a slow rise at long wavelengths were observed. Both features reveal an energy transfer process from isolated to aggregated chains. The contribution of the energy transfer process as well as of the isolated chains and the aggregates on the overall fluorescence decay of the polymer was determined. The dependence of the energy transfer rate and efficiency on polymer concentration was also examined.
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Affiliation(s)
- Mihalis Fakis
- Department of Physics, University of Patras, Patras 26500, Greece.
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17
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Anestopoulos D, Fakis M, Persephonis P, Giannetas V, Mikroyannidis J. Excitation energy transfer in a cationic water-soluble conjugated co-polymer studied by time resolved anisotropy and fluorescence dynamics. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.01.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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Interactions between surfactants and {1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2005.05.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Schmit JD, Levine AJ. Intermolecular adhesion in conducting polymers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:051802. [PMID: 16089562 DOI: 10.1103/physreve.71.051802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Revised: 03/09/2005] [Indexed: 05/03/2023]
Abstract
We analyze the interaction of two conducting, charged polymer chains in solution using a minimal model for their electronic degrees of freedom. We show that a crossing of the two chains in which the polymers pass within angstroms of each other leads to a decrease of the electronic energy of the combined system that is significantly larger than the thermal energy and thus promotes interchain aggregation. We consider the competition of this attractive interaction with the screened electrostatic repulsion and thereby propose a phase diagram for such polymers in solution; depending on the charge density and persistence length of the chains, the polymers may be unbound, bound in loose, braidlike structures, or tightly bound in a parallel configuration.
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Affiliation(s)
- Jeremy D Schmit
- Biomolecular Science and Engineering Program and Materials Research Laboratory, University of California-Santa Barbara, Santa Barbara, CA 93106, USA.
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20
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Knaapila M, Stepanyan R, Torkkeli M, Lyons BP, Ikonen TP, Almásy L, Foreman JP, Serimaa R, Güntner R, Scherf U, Monkman AP. Influence of molecular weight on the phase behavior and structure formation of branched side-chain hairy-rod polyfluorene in bulk phase. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:041802. [PMID: 15903692 DOI: 10.1103/physreve.71.041802] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Indexed: 05/02/2023]
Abstract
We report on an experimental study of the self-organization and phase behavior of hairy-rod pi -conjugated branched side-chain polyfluorene, poly[9,9-bis(2-ethylhexyl)-fluorene-2,7-diyl]-i.e., poly[2,7-(9,9-bis(2-ethylhexyl)fluorene] (PF2/6) -as a function of molecular weight (M(n)) . The results have been compared to those of phenomenological theory. Samples for which M(n) =3-147 kg/mol were used. First, the stiffness of PF2/6 , the assumption of the theory, has been probed by small-angle neutron scattering in solution. Thermogravimetry has been used to show that PF2/6 is thermally stable over the conditions studied. Second, the existence of nematic and hexagonal phases has been phenomenologically identified for lower and higher M(n) (LMW, M(n) < M(*)(n) and HMW, M(n) > M(*)(n) ) regimes, respectively, based on free-energy argument of nematic and hexagonal hairy rods and found to correspond to the experimental x-ray diffraction (XRD) results for PF2/6 . By using the lattice parameters of PF2/6 as an experimental input, the nematic-hexagonal transition has been predicted in the vicinity of glassification temperature (T(g)) of PF2/6 . Then, by taking the orientation parts of the free energies into account the nematic-hexagonal transition has been calculated as a function of temperature and M(n) and a phase diagram has been formed. Below T(g) of 80 degrees C only (frozen) nematic phase is observed for M(n)< M(*)(n) = 10(4) g/mol and crystalline hexagonal phase for M(n) > M(*)(n) . The nematic-hexagonal transition upon heating is observed for the HMW regime depending weakly on M(n) , being at 140-165 degrees C for M(n) > M(*)(n). Third, the phase behavior and structure formation as a function of M(n) have been probed using powder and fiber XRD and differential scanning calorimetry and reasonable semiquantitative agreement with theory has been found for M(n) >or=3 kg/mol. Fourth, structural characteristics are widely discussed. The nematic phase of LMW materials has been observed to be denser than high-temperature nematic phase of HMW compounds. The hexagonal phase has been found to be paracrystalline in the (ab0) plane but a genuine crystal meridionally. We also find that all these materials including the shortest 10-mer possess the formerly observed rigid five-helix hairy-rod molecular structure.
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Affiliation(s)
- M Knaapila
- Department of Physics, University of Durham, South Road, Durham DH1 3LE, United Kingdom.
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Rheological and structural properties of aqueous solutions of a hydrophobically modified polyelectrolyte and its unmodified analogue. Eur Polym J 2004. [DOI: 10.1016/j.eurpolymj.2003.12.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Fan QL, Lu S, Lai YH, Hou XY, Huang W. Synthesis, Characterization, and Fluorescence Quenching of Novel Cationic Phenyl-Substituted Poly(p-phenylenevinylene)s. Macromolecules 2003. [DOI: 10.1021/ma030093f] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Yee-Hing Lai
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Republic of Singapore
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Fan C, Wang S, Hong JW, Bazan GC, Plaxco KW, Heeger AJ. Beyond superquenching: hyper-efficient energy transfer from conjugated polymers to gold nanoparticles. Proc Natl Acad Sci U S A 2003; 100:6297-301. [PMID: 12750470 PMCID: PMC164440 DOI: 10.1073/pnas.1132025100] [Citation(s) in RCA: 318] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gold nanoparticles quench the fluorescence of cationic polyfluorene with Stern-Volmer constants (KSV) approaching 1011 M-1, several orders of magnitude larger than any previously reported conjugated polymer-quencher pair and 9-10 orders of magnitude larger than small molecule dye-quencher pairs. The dependence of KSV on ionic strength, charge and conjugation length of the polymer, and the dimensions (and thus optical properties) of the nanoparticles suggests that three factors account for this extraordinary efficiency: (i) amplification of the quenching via rapid internal energy or electron transfer, (ii) electrostatic interactions between the cationic polymer and anionic nanoparticles, and (iii) the ability of gold nanoparticles to quench via efficient energy transfer. As a result of this extraordinarily high KSV, quenching can be observed even at subpicomolar concentrations of nanoparticles, suggesting that the combination of conjugated polymers with these nanomaterials can potentially lead to improved sensitivity in optical biosensors.
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Affiliation(s)
- Chunhai Fan
- Institute for Polymers and Organic Solids, University of California, Santa Barbara 93106, USA
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Wang D, Gong X, Heeger PS, Rininsland F, Bazan GC, Heeger AJ. Biosensors from conjugated polyelectrolyte complexes. Proc Natl Acad Sci U S A 2002; 99:49-53. [PMID: 11756675 PMCID: PMC117512 DOI: 10.1073/pnas.012581399] [Citation(s) in RCA: 250] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A charge neutral complex (CNC) was formed in aqueous solution by combining an orange light emitting anionic conjugated polyelectrolyte and a saturated cationic polyelectrolyte at a 1:1 ratio (per repeat unit). Photoluminescence (PL) from the CNC can be quenched by both the negatively charged dinitrophenol (DNP) derivative, (DNP-BS(-)), and positively charged methyl viologen (MV(2+)). Use of the CNC minimizes nonspecific interactions (which modify the PL) between conjugated polyelectrolytes and biopolymers. Quenching of the PL from the CNC by the DNP derivative and specific unquenching on addition of anti-DNP antibody (anti-DNP IgG) were observed. Thus, biosensing of the anti-DNP IgG was demonstrated.
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Affiliation(s)
- Deli Wang
- Institute for Polymers and Organic Solids and Materials Department, University of California, Santa Barbara, CA 93106-5090, USA
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