1
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Martens CM. Critical adsorption and charge reversal in polyelectrolyte solutions: Analytical mean-field theory. J Chem Phys 2024; 161:054901. [PMID: 39087544 DOI: 10.1063/5.0222386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 07/17/2024] [Indexed: 08/02/2024] Open
Abstract
An analytical linearized mean-field theory is presented to describe the adsorption behavior of polyelectrolytes near charged colloidal surfaces with additional short-ranged non-electrostatic interactions. The coupling between the polyelectrolyte segment density and electrostatic potential is explicitly accounted for in a self-consistent manner. This coupling gives rise to highly non-linear behavior, such as oscillations of the electrostatic potential. We derive analytical expressions for the critical surface charge density σc, after which adsorption takes place, and recover the well-known σc∼ns3/2 scaling regime, where ns is the salt concentration. In addition, the theory yields a new ns1 scaling regime if the surface is hard and a unified ns1 scaling regime if the surface also possesses some short-ranged attraction with the polyelectrolyte. Furthermore, we derive an analytical expression to describe the critical polyelectrolyte concentration φc to achieve complete charge reversal, which is found to scale as φc ∼ σ2/(f2c2), where c is related to the magnitude of short-ranged interactions and f is the average charge per monomer of the polyelectrolyte. It is observed that within our theory, complete charge reversal can only take place if the short-ranged interactions are sufficiently strong to completely compensate for the entropy loss of adsorption.
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Affiliation(s)
- C M Martens
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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2
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Bong JH, Grebenchuk S, Nikolaev KG, Chee CPT, Yang K, Chen S, Baranov D, Woods CR, Andreeva DV, Novoselov KS. Graphene oxide-DNA/graphene oxide-PDDA sandwiched membranes with neuromorphic function. NANOSCALE HORIZONS 2024; 9:863-872. [PMID: 38533738 DOI: 10.1039/d3nh00570d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The behavior of polyelectrolytes in confined spaces has direct relevance to the protein mediated ion transport in living organisms. In this paper, we govern lithium chloride transport by the interface provided by polyelectrolytes, polycation, poly(diallyldimethylammonium chloride) (PDDA) and, polyanion, double stranded deoxyribonucleic acid (dsDNA), in confined graphene oxide (GO) membranes. Polyelectrolyte-GO interfaces demonstrate neuromorphic functions that were successfully applied with nanochannel ion interactions contributed, resulting in ion memory effects. Excitatory and inhibitory post-synaptic currents were tuned continuously as the number of pulses applied increased accordingly, increasing decay times. Furthermore, we demonstrated the short-term memory of a trained vs untrained device in computation. On account of its simple and safe production along with its robustness and stability, we anticipate our device to be a low dimensional building block for arrays to embed artificial neural networks in hardware for neuromorphic computing. Additionally, incorporating such devices with sensing and actuating parts for a complete feedback loop produces robotics with its own ability to learn by modifying actuation based on sensing data.
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Affiliation(s)
- Jia Hui Bong
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Sergey Grebenchuk
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Konstantin G Nikolaev
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
| | - Celestine P T Chee
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Kou Yang
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
| | - Siyu Chen
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Denis Baranov
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
| | - Colin R Woods
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Daria V Andreeva
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Kostya S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
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3
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Zhou S, Nadeau EA, Khan MA, Webb BA, Rankin SE, Knutson BL. Relating Mobility of dsRNA in Nanoporous Silica Particles to Loading and Release Behavior. ACS APPLIED BIO MATERIALS 2021; 4:8267-8276. [DOI: 10.1021/acsabm.1c00810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shanshan Zhou
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Emily A. Nadeau
- Department of Entomology, University of Kentucky, Lexington, Kentucky 40546, United States
| | - M. Arif Khan
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Bruce A. Webb
- Department of Entomology, University of Kentucky, Lexington, Kentucky 40546, United States
| | - Stephen E. Rankin
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Barbara L. Knutson
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
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4
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Caetano DLZ, Metzler R, Cherstvy AG, de Carvalho SJ. Adsorption of lysozyme into a charged confining pore. Phys Chem Chem Phys 2021; 23:27195-27206. [PMID: 34821240 DOI: 10.1039/d1cp03185f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Several applications arise from the confinement of proteins on surfaces because their stability and biological activity are enhanced. It is also known that the way in which a protein adsorbs on the surface is important for its biological function since its active sites should not be obstructed. In this study, the adsorption properties of hen egg-white lysozyme, HEWL, into a negatively charged silica pore is examined by employing a coarse-grained model and constant-pH Monte Carlo simulations. The role of electrostatic interactions is taken into account via including the Debye-Hückel potentials into the Cα structure-based model. We evaluate the effects of pH, salt concentration, and pore radius on the protein preferential orientation and spatial distribution of its residues regarding the pore surface. By mapping the residues that stay closer to the pore surface, we find that the increase of pH leads to orientational changes of the adsorbed protein when the solution pH gets closer to the HEWL isoelectric point. Under these conditions, the pKa shift of these important residues caused by the adsorption into the charged confining surface results in a HEWL charge distribution that stabilizes the adsorption in the observed protein orientation. We compare our observations to the results of the pKa shift for HEWL available in the literature and to some experimental data.
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Affiliation(s)
- Daniel L Z Caetano
- Institute of Chemistry, State University of Campinas (UNICAMP), Campinas, Brazil.,Center for Computational Engineering and Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Ralf Metzler
- Institute for Physics & Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Andrey G Cherstvy
- Institute for Physics & Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany.,Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Sidney J de Carvalho
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, Brazil.
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5
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Jiang S, Förster R, Lorenz A, Schmidt MA. Three-dimensional tracking of nanoparticles by dual-color position retrieval in a double-core microstructured optical fiber. LAB ON A CHIP 2021; 21:4437-4444. [PMID: 34617084 DOI: 10.1039/d1lc00709b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Elastic light scattering-based three-dimensional (3D) tracking of objects at the nanoscale level is essential for unlocking the dynamics of individual species or interactions in fields such as biology or surface chemistry. In this work, we introduce the concept of dual-color 3D tracking in a double-core microstructured optical fiber that for the first time allows for full 3D reconstruction of the trajectory of a diffusing nanoparticle in a water-filled fiber-integrated microchannel. The use of two single-mode cores provides two opposite decaying evanescent fields of different wavelengths within the microchannel, bypassing spatial domains of ambiguous correlation between the scattered intensity and position. The novelty of the fiber design is the use of two slightly different single-mode cores, preventing modal crosstalk and thus allowing for longitudinally invariant dual-color illumination across the entire field of view. To demonstrate the capabilities of the scheme, a single gold nanosphere (80 nm) diffusing in the water-filled microchannel was tracked for a large number of images (about 32 000) at a high frame rate (1.389 kHz) over a long time (23 s), with the determined hydrodynamic diameters matching expectations. The presented 3D tracking approach yields unique opportunities to unlock processes at the nanoscale level and is highly relevant for a multitude of fields, particularly within the context of understanding sophisticated interaction of diffusing species with functionalized surfaces within the context of bioanalytics, nanoscale materials science, surface chemistry or life science.
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Affiliation(s)
- Shiqi Jiang
- Leibniz Institute of Photonic Technology, 07745, Jena, Germany.
- Abbe Center of Photonics and Faculty of Physics, FSU Jena, 07745 Jena, Germany
| | - Ronny Förster
- Leibniz Institute of Photonic Technology, 07745, Jena, Germany.
| | - Adrian Lorenz
- Leibniz Institute of Photonic Technology, 07745, Jena, Germany.
| | - Markus A Schmidt
- Leibniz Institute of Photonic Technology, 07745, Jena, Germany.
- Abbe Center of Photonics and Faculty of Physics, FSU Jena, 07745 Jena, Germany
- Otto Schott Institute of Material Research, FSU Jena, 07745 Jena, Germany
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6
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Ghosh S, Vemparala S. Kinetics of charged polymer collapse in poor solvents. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:045101. [PMID: 34352747 DOI: 10.1088/1361-648x/ac1aef] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Extensive molecular dynamics simulations, using simple charged polymer models, have been employed to probe the collapse kinetics of a single flexible polyelectrolyte (PE) chain under implicit poor solvent conditions. We investigate the role of the charged nature of PE chain (A), valency of counterions (Z) on the kinetics of such PE collapse. Our study shows that the collapse kinetics of charged polymers are significantly different from those of the neutral polymer and that the finite-size scaling behavior of PE collapse times does not follow the Rouse scaling as observed in the case of neutral polymers. The critical exponent for charged PE chains is found to be less than that of neutral polymers and also exhibits dependence on counterion valency. The coarsening of clusters along the PE chain suggests a multi-stage collapse and exhibits opposite behavior of exponents compared to neutral polymers: faster in the early stages and slower in the later stages of collapse.
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Affiliation(s)
- Susmita Ghosh
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
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7
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Huang C, Podgornik R, Man X. Selective Adsorption of Confined Polymers: Self-Consistent Field Theory Studies. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Changhang Huang
- Center of Soft Matter Physics and its Applications, Beihang University, Beijing 100191, China
- School of Physics, Beihang University, Beijing 100191, China
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing 100190, China
- Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Xingkun Man
- Center of Soft Matter Physics and its Applications, Beihang University, Beijing 100191, China
- School of Physics, Beihang University, Beijing 100191, China
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8
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Milchev A, Binder K. Adsorption of Semiflexible Polymers in Cylindrical Tubes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11759-11770. [PMID: 34581575 DOI: 10.1021/acs.langmuir.1c01715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Conformations of wormlike chains in cylindrical pores with attractive walls are explored for varying pore radius and strength of the attractive wall potential by molecular dynamics simulations of a coarse-grained model. Local quantities such as the fraction of monomeric units bound to the surface and the bond-orientational order parameter as well as the radial density distribution are studied, as well as the global chain extensions parallel to the cylinder axis and perpendicular to the cylinder surface. A nonmonotonic convergence of these properties to their counterparts for adsorption on a planar substrate is observed due to the conflict between pore surface curvature and chain stiffness. Also the interpretation of partially adsorbed chains in terms of trains, loops, and tails is discussed.
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Affiliation(s)
- A Milchev
- Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - K Binder
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 9, D-55099 Mainz, Germany
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9
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Affiliation(s)
- Qiuhui Chang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jian Jiang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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10
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Emanuel MD, Cherstvy AG, Metzler R, Gompper G. Buckling transitions and soft-phase invasion of two-component icosahedral shells. Phys Rev E 2021; 102:062104. [PMID: 33465945 DOI: 10.1103/physreve.102.062104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 11/11/2020] [Indexed: 12/18/2022]
Abstract
What is the optimal distribution of two types of crystalline phases on the surface of icosahedral shells, such as of many viral capsids? We here investigate the distribution of a thin layer of soft material on a crystalline convex icosahedral shell. We demonstrate how the shapes of spherical viruses can be understood from the perspective of elasticity theory of thin two-component shells. We develop a theory of shape transformations of an icosahedral shell upon addition of a softer, but still crystalline, material onto its surface. We show how the soft component "invades" the regions with the highest elastic energy and stress imposed by the 12 topological defects on the surface. We explore the phase diagram as a function of the surface fraction of the soft material, the shell size, and the incommensurability of the elastic moduli of the rigid and soft phases. We find that, as expected, progressive filling of the rigid shell by the soft phase starts from the most deformed regions of the icosahedron. With a progressively increasing soft-phase coverage, the spherical segments of domes are filled first (12 vertices of the shell), then the cylindrical segments connecting the domes (30 edges) are invaded, and, ultimately, the 20 flat faces of the icosahedral shell tend to be occupied by the soft material. We present a detailed theoretical investigation of the first two stages of this invasion process and develop a model of morphological changes of the cone structure that permits noncircular cross sections. In conclusion, we discuss the biological relevance of some structures predicted from our calculations, in particular for the shape of viral capsids.
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Affiliation(s)
- Marc D Emanuel
- Theoretical Physics of Living Matter, Institute of Biological Information Processing, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.,Kavli Institute for Nanoscience, Technical University Delft, 2628 CJ Delft, Netherlands
| | - Andrey G Cherstvy
- Theoretical Physics of Living Matter, Institute of Biological Information Processing, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.,Institute for Physics & Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Ralf Metzler
- Institute for Physics & Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Gerhard Gompper
- Theoretical Physics of Living Matter, Institute of Biological Information Processing, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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11
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Khan MA, Kiser MR, Moradipour M, Nadeau EA, Ghanim RW, Webb BA, Rankin SE, Knutson BL. Effect of Confinement in Nanopores on RNA Interactions with Functionalized Mesoporous Silica Nanoparticles. J Phys Chem B 2020; 124:8549-8561. [PMID: 32881500 DOI: 10.1021/acs.jpcb.0c06536] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Amine-functionalized mesoporous silica nanoparticles (MSNPAs) are ideal carriers for oligonucleotides for gene delivery and RNA interference. This investigation examines the thermodynamic driving force of interactions of double-stranded (ds) RNA with MSNPAs as a function of RNA length (84 and 282 base pair) and particle pore diameter (nonporous, 2.7, 4.3, and 8.1 nm) using isothermal titration calorimetry, extending knowledge of solution-based nucleic acid-polycation interactions to RNA confined in nanopores. Adsorption of RNA follows a two-step process: endothermic interactions driven by entropic contribution from counterion (and water) release and an exothermic regime dominated by short-range interactions within the pores. Evidence of hindered pore loading of the longer RNA and pore size-dependent confinement of RNA in the MSPAs is provided from the relative contributions of the endothermic and exothermic regimes. Reduction of endothermic and exothermic enthalpies in both regimes in the presence of salt for both lengths of RNA indicates the significant contribution of short-range electrostatic interactions, whereas ΔH and ΔG values are consistent with conformation changes and desolvation of nucleic acids upon binding with polycations. Knowledge of the interactions between RNA and functionalized porous nanoparticles will aid in porous nanocarrier design suitable for functional RNA delivery.
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Affiliation(s)
- M Arif Khan
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Maelyn R Kiser
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Mahsa Moradipour
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Emily A Nadeau
- Department of Entomology, University of Kentucky, Lexington, Kentucky 40546, United States
| | - Ramy W Ghanim
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Bruce A Webb
- Department of Entomology, University of Kentucky, Lexington, Kentucky 40546, United States
| | - Stephen E Rankin
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Barbara L Knutson
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
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12
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Wang T, Wang S, Tong C. Charge reversal in the collapse of polyelectrolyte star brushes under an electric field. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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13
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Caetano DLZ, de Carvalho SJ, Metzler R, Cherstvy AG. Critical adsorption of multiple polyelectrolytes onto a nanosphere: splitting the adsorption-desorption transition boundary. J R Soc Interface 2020; 17:20200199. [PMID: 32574545 PMCID: PMC7328387 DOI: 10.1098/rsif.2020.0199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/03/2020] [Indexed: 01/09/2023] Open
Abstract
Employing extensive Monte Carlo computer simulations, we investigate in detail the properties of multichain adsorption of charged flexible polyelectrolytes (PEs) onto oppositely charged spherical nanoparticles (SNPs). We quantify the conditions of critical adsorption-the phase-separation curve between the adsorbed and desorbed states of the PEs-as a function of the SNP surface-charge density and the concentration of added salt. We study the degree of fluctuations of the PE-SNP electrostatic binding energy, which we use to quantify the emergence of the phase subtransitions, including a series of partially adsorbed PE configurations. We demonstrate how the phase-separation adsorption-desorption boundary shifts and splits into multiple subtransitions at low-salt conditions, thereby generalizing and extending the results for critical adsorption of a single PE onto the SNP. The current findings are relevant for finite concentrations of PEs around the attracting SNP, such as the conditions for PE adsorption onto globular proteins carrying opposite electric charges.
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Affiliation(s)
- Daniel L. Z. Caetano
- São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, Campus São José do Rio Preto, 15054-000 Brazil
- Institute of Chemistry, State University of Campinas (UNICAMP), 13083-970 Campinas, Brazil
- Center for Computational Engineering and Sciences, State University of Campinas (UNICAMP), 13083-970 Campinas, Brazil
| | - Sidney J. de Carvalho
- São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, Campus São José do Rio Preto, 15054-000 Brazil
| | - Ralf Metzler
- Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Andrey G. Cherstvy
- Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
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14
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Morrin GT, Kienle DF, Weltz JS, Traeger JC, Schwartz DK. Polyelectrolyte Surface Diffusion in a Nanoslit Geometry. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02365] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gregory T. Morrin
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel F. Kienle
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - James S. Weltz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jeremiah C. Traeger
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel K. Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
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15
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Wu H, Sarfati R, Wang D, Schwartz DK. Electrostatic Barriers to Nanoparticle Accessibility of a Porous Matrix. J Am Chem Soc 2020; 142:4696-4704. [DOI: 10.1021/jacs.9b12096] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Haichao Wu
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Raphaël Sarfati
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Dapeng Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Daniel K. Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
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16
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Mella M, Tagliabue A, Mollica L, Izzo L. Monte Carlo study of the effects of macroion charge distribution on the ionization and adsorption of weak polyelectrolytes and concurrent counterion release. J Colloid Interface Sci 2020; 560:667-680. [PMID: 31704002 DOI: 10.1016/j.jcis.2019.10.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 01/16/2023]
Abstract
HYPOTHESIS Adsorption of weak polyelectrolytes onto charged nanoparticles, and concurrent effects such as spatial partitioning of ions may be influenced by details of the polyelectrolyte structure (linear or star-like) and size, by the mobility of the nanoparticle surface charge, or the valence of the nanoparticle counterions. EXPERIMENTS Ionization and complexation of weak polyelectrolytes on spherical macroions with monovalent and divalent countrions has been studied with constant-pH Monte Carlo titrations and primitive electrolyte models for linear and star-like polymers capable, also, of forming charged hydrogen bonds. Nanoparticles surface charge has been represented either as a single colloid-centered total charge (CCTC) or as surface-tethered mobile monovalent spherical charges (SMMSC). FINDINGS Differences in the average number of adsorbed polyelectrolyte arms and their average charge, and in the relative amount of macroion counterions (m-CI's) released upon polymer adsorption are found between CCTC and SMMSC nanoparticles. The amount of the counterions released also depends on the polymer structure. As CCTC adsorbs a lower number of star-like species arms, the degree of condensation of polymer counterions (p-CI's) onto the polyelectrolyte is also substantially higher for the CCTC colloid, with a concurrent decrease of the osmotic coefficient values.
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Affiliation(s)
- Massimo Mella
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 11, 22100 Como, Italy.
| | - Andrea Tagliabue
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 11, 22100 Como, Italy
| | - Luca Mollica
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, 20133 Milano, Italy; Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi", Via F. Sforza 35, 20122 Milano, Italy
| | - Lorella Izzo
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy.
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17
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Shin S, Kim HS, Kim MI, Lee J, Park HG, Kim J. Crowding and confinement effects on enzyme stability in mesoporous silicas. Int J Biol Macromol 2020; 144:118-126. [DOI: 10.1016/j.ijbiomac.2019.12.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 11/26/2022]
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18
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Zhang C, Sun G, Senapati S, Chang HC. A bifurcated continuous field-flow fractionation (BCFFF) chip for high-yield and high-throughput nucleic acid extraction and purification. LAB ON A CHIP 2019; 19:3853-3861. [PMID: 31621762 PMCID: PMC6982425 DOI: 10.1039/c9lc00818g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We report a bifurcated continuous field-flow fractionation (BCFFF) chip for high-yield and high-throughput (20 min) extraction of nucleic acids from physiological samples. The design uses a membrane ionic transistor to sustain low-ionic strength in a localized region at a junction, such that the resulting high field can selectively isolate high-charge density nucleic acids from the main flow channel and insert them into a standardized buffer in a side channel that bifurcates from the junction. The high local electric field and the bifurcated field-flow design facilitate concentration reduction of both divalent cation (Ca2+) and molecular PCR inhibitors by more than two orders of magnitude, even with high-throughput continuous loading. The unique design with a large (>20 mM mm-1) on-chip ionic-strength gradient allows miniaturization into a high-throughput field-flow fractionation chip that can be integrated with upstream lysing and downstream PCR/sensor modules for various nucleic acid detection/quantification applications. A concentration-independent 85% yield for extraction and an overall post-PCR yield exceeding 60% are demonstrated for a 111 bp dsDNA in 10 μL of human plasma, compared to no amplification with the raw sample. A net yield four times larger than a commercial extraction kit is demonstrated for miR-39 in human plasma.
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Affiliation(s)
- Chenguang Zhang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. and Center for Microfluidics and Medical Diagnostics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Gongchen Sun
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Satyajyoti Senapati
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. and Center for Microfluidics and Medical Diagnostics, University of Notre Dame, Notre Dame, IN 46556, USA and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Hsueh-Chia Chang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. and Center for Microfluidics and Medical Diagnostics, University of Notre Dame, Notre Dame, IN 46556, USA and Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA and Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
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19
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Wang D, Wu H, Liu L, Chen J, Schwartz DK. Diffusive Escape of a Nanoparticle from a Porous Cavity. PHYSICAL REVIEW LETTERS 2019; 123:118002. [PMID: 31573262 DOI: 10.1103/physrevlett.123.118002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/26/2019] [Indexed: 06/10/2023]
Abstract
Narrow escape from confinement through a nanochannel is the critical step of complex transport processes including size-exclusion-based separations, oil and gas extraction from the microporous subsurface environment, and ribonucleic acid translocation through nuclear pore complex channels. While narrow escape has been studied using theoretical and computational methods, experimental quantification is rare because of the difficulty in confining a particle into a microscopic space through a nanoscale hole. Here, we studied narrow escape in the context of continuous nanoparticle diffusion within the liquid-filled void space of an ordered porous material. Specifically, we quantified the spatial dependence of nanoparticle motion and the sojourn times of individual particles in the interconnected confined cavities of a liquid-filled inverse opal film. We found that nanoparticle motion was inhibited near cavity walls and cavity escape was slower than predicted by existing theories and random-walk simulations. A combined computational-experimental analysis indicated that translocation through a nanochannel is barrier controlled rather than diffusion controlled.
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Affiliation(s)
- Dapeng Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Peoples Republic of China
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Haichao Wu
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Lijun Liu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Peoples Republic of China
| | - Jizhong Chen
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Peoples Republic of China
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
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20
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Cao Q. Anisotropic electrokinetic transport in channels modified with patterned polymer brushes. SOFT MATTER 2019; 15:4132-4145. [PMID: 31045197 DOI: 10.1039/c9sm00385a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Molecular dynamics simulations have been used to predict the transport dynamics of fluids through nanochannels with polymer patterning surfaces. The effects of different parameters, such as separation between polymer stripes, solvent quality, and direction and strength of the electric field, were explored in terms of electroosmotic flow transport characteristics, conformational dynamics of the polymer brush and ion distribution. Anisotropic electrokinetic transport becomes significant due to the surface patterning of polymers when the direction of the electric field is changed. At the separation between adjacent polymer stripes comparable to the chain length, local strong flow close to the bare surfaces weakens dramatically under the electric field along the stripe direction. However, when the electric field is switched to the direction perpendicular to the stripes, the flow is enhanced considerably. The coupling of the polymer solvent quality further richens and complicates the transport behaviors. We explain the physical mechanism of the electroosmotic flow in complex polymer patterning channels by analyzing the interrelationship among various properties.
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Affiliation(s)
- Qianqian Cao
- College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001, P. R. China.
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21
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Morrin GT, Kienle DF, Schwartz DK. Standalone interferometry-based calibration of convex lens-induced confinement microscopy with nanoscale accuracy. Analyst 2019; 144:2628-2634. [PMID: 30839956 PMCID: PMC6779313 DOI: 10.1039/c8an02300j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Strongly confined environments (confined dimensions between 1-100 nm) represent unique challenges and opportunities for understanding and manipulating molecular behavior due to the significant effects of electric double layers, high surface-area to volume ratios, and other phenomena at the nanoscale. Convex Lens-induced Confinement (CLiC) can be used to analyze the dynamics of individual molecules or particles confined in a planar slit geometry with continuously varying gap thickness. We describe an interferometry-based method for precise measurement of the slit pore geometry. Specifically, this approach permitted accurate characterization of separation distances as small as 5 nm, with 1 nm precision, without a priori knowledge or assumptions about the contact geometry, as well as a greatly simplified experimental setup that required only a lens, coverslip, and inverted microscope. The interferometry-based measurement of gap height offered a distinct advantage over conventional fluorescent dye-based methods; e.g., accurate interferometric height measurements were made at low gap heights regardless of solution conditions, while the concentration of fluorescent dye was significantly impacted by solution conditions such as ionic strength or pH. The accuracy of the interferometric measurements was demonstrated by comparing the experimentally measured concentration of a charged fluorescent dye as a function of gap thickness with dye concentration profiles calculated using Debye-Hückel theory. Accurate characterization of nanoscale gap thickness will enable researchers to study a variety of practical and biologically relevant systems within the CLiC geometry.
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Affiliation(s)
- Gregory T Morrin
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA.
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22
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Tagliabue A, Izzo L, Mella M. Absorbed weak polyelectrolytes: Impact of confinement, topology, and chemically specific interactions on ionization, conformation free energy, counterion condensation, and absorption equilibrium. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24806] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Andrea Tagliabue
- Dipartimento di Scienza ed Alta TecnologiaUniversità degli Studi dell'Insubria via Valleggio 9, 22100, Como Italy
| | - Lorella Izzo
- Dipartimento di Biotecnologie e Scienze della VitaUniversità degli Studi dell'Insubria via J. H. Dunant 3, 21100, Varese Italy
| | - Massimo Mella
- Dipartimento di Scienza ed Alta TecnologiaUniversità degli Studi dell'Insubria via Valleggio 9, 22100, Como Italy
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23
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Luque-Caballero G, Maldonado-Valderrama J, Quesada-Pérez M, Martín-Molina A. Interaction of DNA with likely-charged lipid monolayers: An experimental study. Colloids Surf B Biointerfaces 2019; 178:170-176. [PMID: 30856586 DOI: 10.1016/j.colsurfb.2019.02.058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 12/31/2022]
Abstract
Anionic lipids are increasingly being used in lipoplexes for synthetic gene vectors as an alternative to cationic lipids. This is primarily due to their lower toxicity, which makes them biocompatible and adaptable to be tissue specific. However, anionic lipoplexes require the presence of multivalent cations to promote the electrostatic attraction between DNA and anionic lipid mono- and bilayers. In this work we provide for the first time experimental results of the adsorption of linear DNA onto anionic/zwitterionic lipid monolayers without any addition of cations. This is demonstrated experimentally by means of Langmuir monolayers of DOPE/DOPG (1:1) lipids spread on a water subphase that contains calf thymus DNA. The adsorption of DNA onto anionic/zwitterionic lipid monolayers is discussed in terms of the surface pressure-molecular area isotherms recorded in the absence and in the presence of different electrolytes. Measurements of the surface potential provide additional evidence of the different interaction of DNA anionic/zwitterionic lipid monolayers depending on the presence and nature of electrolyte. These experimental results are further analysed in terms of the overall dipole moment normal to the monolayers providing new insight into the behaviour of anionic lipoplexes and the role of zwitterionic lipids.
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Affiliation(s)
- German Luque-Caballero
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, 18071, Granada, Spain
| | - Julia Maldonado-Valderrama
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, 18071, Granada, Spain; Unidad de excelencia "Modelling Nature" (MNat), Universidad de Granada, Spain
| | - Manuel Quesada-Pérez
- Departamento de Física, Escuela Politécnica Superior de Linares, Universidad de Jaén, 23700, Linares, Jaén, Spain
| | - Alberto Martín-Molina
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, 18071, Granada, Spain; Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Spain.
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24
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Landsgesell J, Nová L, Rud O, Uhlík F, Sean D, Hebbeker P, Holm C, Košovan P. Simulations of ionization equilibria in weak polyelectrolyte solutions and gels. SOFT MATTER 2019; 15:1155-1185. [PMID: 30706070 DOI: 10.1039/c8sm02085j] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This article recapitulates the state of the art regarding simulations of ionization equilibria of weak polyelectrolyte solutions and gels. We start out by reviewing the essential thermodynamics of ionization and show how the weak polyelectrolyte ionization differs from the ionization of simple weak acids and bases. Next, we describe simulation methods for ionization reactions, focusing on two methods: the constant-pH ensemble and the reaction ensemble. After discussing the advantages and limitations of both methods, we review the existing simulation literature. We discuss coarse-grained simulations of weak polyelectrolytes with respect to ionization equilibria, conformational properties, and the effects of salt, both in good and poor solvent conditions. This is followed by a discussion of branched star-like weak polyelectrolytes and weak polyelectrolyte gels. At the end we touch upon the interactions of weak polyelectrolytes with other polymers, surfaces, nanoparticles and proteins. Although proteins are an important class of weak polyelectrolytes, we explicitly exclude simulations of protein ionization equilibria, unless they involve protein-polyelectrolyte interactions. Finally, we try to identify gaps and open problems in the existing simulation literature, and propose challenges for future development.
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Affiliation(s)
- Jonas Landsgesell
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, Stuttgart, Germany.
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25
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Shojaei HR, Muthukumar M. Adsorption and encapsulation of flexible polyelectrolytes in charged spherical vesicles. J Chem Phys 2018; 146:244901. [PMID: 28668020 DOI: 10.1063/1.4986961] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a theory of adsorption of flexible polyelectrolytes on the interior and exterior surfaces of a charged vesicle in an electrolyte solution. The criteria for adsorption and the density profiles of the adsorbed polymer chain are derived in terms of various characteristics of the polymer, vesicle, and medium, such as the charge density and length of the polymer, charge density and size of the vesicle, electrolyte concentration and dielectric constant of the medium. For adsorption inside the vesicle, the competition between the loss of conformational entropy and gain in adsorption energy results in two kinds of encapsulated states, depending on the strength of the polymer-vesicle interaction. By considering also the adsorption from outside the vesicle, we derive the entropic and energy contributions to the free energy change to transfer an adsorbed chain in the interior to an adsorbed chain on the exterior. In this paper, we have used the Wentzel-Kramers-Brillouin (WKB) method to solve the equation for the probability distribution function of the chain. The present WKB results are compared with the previous results based on variational methods. The WKB and variational results are in good agreement for both the interior and exterior states of adsorption, except in the zero-salt limit for adsorption in the exterior region. The adsorption criteria and density profiles for both the interior and exterior states are presented in terms of various experimentally controllable variables. Calculation of the dependencies of free energy change to transfer an adsorbed chain from the interior to the exterior surface on salt concentration and vesicle radius shows that the free energy penalty to expel a chain from a vesicle is only of the order of thermal energy.
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Affiliation(s)
- H R Shojaei
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - M Muthukumar
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
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26
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Sentker K, Zantop AW, Lippmann M, Hofmann T, Seeck OH, Kityk AV, Yildirim A, Schönhals A, Mazza MG, Huber P. Quantized Self-Assembly of Discotic Rings in a Liquid Crystal Confined in Nanopores. PHYSICAL REVIEW LETTERS 2018; 120:067801. [PMID: 29481274 DOI: 10.1103/physrevlett.120.067801] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/21/2017] [Indexed: 05/16/2023]
Abstract
Disklike molecules with aromatic cores spontaneously stack up in linear columns with high, one-dimensional charge carrier mobilities along the columnar axes, making them prominent model systems for functional, self-organized matter. We show by high-resolution optical birefringence and synchrotron-based x-ray diffraction that confining a thermotropic discotic liquid crystal in cylindrical nanopores induces a quantized formation of annular layers consisting of concentric circular bent columns, unknown in the bulk state. Starting from the walls this ring self-assembly propagates layer by layer towards the pore center in the supercooled domain of the bulk isotropic-columnar transition and thus allows one to switch on and off reversibly single, nanosized rings through small temperature variations. By establishing a Gibbs free energy phase diagram we trace the phase transition quantization to the discreteness of the layers' excess bend deformation energies in comparison to the thermal energy, even for this near room-temperature system. Monte Carlo simulations yielding spatially resolved nematic order parameters, density maps, and bond-orientational order parameters corroborate the universality and robustness of the confinement-induced columnar ring formation as well as its quantized nature.
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Affiliation(s)
- Kathrin Sentker
- Institut für Materialphysik und -technologie, Technische Universität Hamburg (TUHH), Eißendorferstr. 42, D-21073 Hamburg, Germany
| | - Arne W Zantop
- Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, D-37077 Göttingen, Germany
| | - Milena Lippmann
- Deutsches Elektronen Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg, Germany
| | - Tommy Hofmann
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Oliver H Seeck
- Deutsches Elektronen Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg, Germany
| | - Andriy V Kityk
- Faculty of Electrical Engineering, Czestochowa University of Technology, Al. Armii Krajowej 17, P-42-200 Czestochowa, Poland
| | - Arda Yildirim
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, D-12205 Berlin, Germany
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, D-12205 Berlin, Germany
| | - Marco G Mazza
- Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, D-37077 Göttingen, Germany
| | - Patrick Huber
- Institut für Materialphysik und -technologie, Technische Universität Hamburg (TUHH), Eißendorferstr. 42, D-21073 Hamburg, Germany
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27
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Angelescu DG. Role of polyion length in the co-assembly of stoichiometric viral-like nanoparticles. JOURNAL OF POLYMER RESEARCH 2017. [DOI: 10.1007/s10965-017-1416-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Caetano DLZ, de Carvalho SJ, Metzler R, Cherstvy AG. Critical adsorption of periodic and random polyampholytes onto charged surfaces. Phys Chem Chem Phys 2017; 19:23397-23413. [PMID: 28825753 DOI: 10.1039/c7cp04040g] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
How different are the properties of critical adsorption of polyampholytes and polyelectrolytes onto charged surfaces? How important are the details of polyampholyte charge distribution on the onset of critical adsorption transition? What are the scaling relations governing the dependence of critical surface charge density on salt concentration in the surrounding solution? Here, we employ Metropolis Monte Carlo simulations and uncover the scaling relations for critical adsorption for quenched periodic and random charge distributions along the polyampholyte chains. We also evaluate and discuss the dependence of the adsorbed layer width on solution salinity and details of the charge distribution. We contrast our findings to the known results for polyelectrolyte adsorption onto oppositely charged surfaces, in particular, their dependence on electrolyte concentration.
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Affiliation(s)
- Daniel L Z Caetano
- Sao Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences (Ibilce), Campus Sao Jose do Rio Preto, 15054-000, Brazil.
| | - Sidney J de Carvalho
- Sao Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences (Ibilce), Campus Sao Jose do Rio Preto, 15054-000, Brazil.
| | - Ralf Metzler
- Institute for Physics & Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany.
| | - Andrey G Cherstvy
- Institute for Physics & Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany.
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29
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Fan Y, Kellermeier M, Xu AY, Boyko V, Mirtschin S, Dubin PL. Modulation of Polyelectrolyte–Micelle Interactions via Zeta Potentials. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00584] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Yaxun Fan
- Department
of Chemistry, University of Massachusetts at Amherst, Amherst, Massachusetts 01003, United States
- Key
Laboratory of Colloid and Interface Science, Beijing National Laboratory
for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Matthias Kellermeier
- Advanced
Materials and Systems Research, BASF SE, Carl-Bosch-Str. 38, D-67056 Ludwigshafen, Germany
| | - Amy Y. Xu
- Department
of Chemistry, University of Massachusetts at Amherst, Amherst, Massachusetts 01003, United States
| | - Volodymyr Boyko
- Advanced
Materials and Systems Research, BASF SE, Carl-Bosch-Str. 38, D-67056 Ludwigshafen, Germany
| | - Sebastian Mirtschin
- Advanced
Materials and Systems Research, BASF SE, Carl-Bosch-Str. 38, D-67056 Ludwigshafen, Germany
| | - Paul L. Dubin
- Department
of Chemistry, University of Massachusetts at Amherst, Amherst, Massachusetts 01003, United States
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30
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Mella M, Izzo L. Modulation of ionization and structural properties of weak polyelectrolytes due to 1D, 2D, and 3D confinement. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24351] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Massimo Mella
- Dipartimento di Scienza ed Alta Tecnologia; Università degli Studi dell'Insubria; via Valleggio 9 Como 22100 Italy
| | - Lorella Izzo
- Dipartimento di Chimica e Biologia; Università degli Studi di Salerno; via Giovanni Paolo II, 132 Fisciano 84084 Italy
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31
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Ahualli S, Martín-Molina A, Maroto-Centeno JA, Quesada-Pérez M. Interaction between Ideal Neutral Nanogels: A Monte Carlo Simulation Study. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02333] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Silvia Ahualli
- Departamento
de Física Aplicada, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Alberto Martín-Molina
- Departamento
de Física Aplicada, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | | | - Manuel Quesada-Pérez
- Departamento
de Física, Escuela Politécnica Superior de Linares, Universidad de Jaén, 23700, Linares, Jaén, Spain
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32
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Caetano DLZ, de Carvalho SJ. Conformational properties of block-polyampholytes adsorbed on charged cylindrical surfaces. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2017; 40:33. [PMID: 28337649 DOI: 10.1140/epje/i2017-11525-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/08/2017] [Indexed: 06/06/2023]
Abstract
Polyampholytes are polymers that have positive and negative monomers along their chain. The adsorption of polyampholytes on charged surfaces has been the subject of a large number of theoretical, computational and experimental studies due to its importance in a variety of bio and nanothechnological systems. However, computational studies focusing on interaction between polyampholytes and cylindrical charged surfaces are rather scarce. This study, therefore, aims to investigate the conformational properties of block-polyampholytes in the presence of a negatively charged cylinder by means of Metropolis Monte Carlo simulations. Adopting a simplified model in which the electrolyte solution is treated at the Debye-Hückel level, the effects of the ionic strength, the linear charge density of the cylinder and the block length on monomers distributions have been investigated. It was found that increasing the salt concentration promotes a transition from a conformation characterized by large loops to a necklace-like conformation parallel to the surface. It was also shown that, at low cylinder charge density, the increase in salt concentration and the length of the blocks lead to a change in the orientation of the adsorbed chain.
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Affiliation(s)
- Daniel L Z Caetano
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Rua Cristovão Colombo 2265, Jd. Nazareth, 15054-000, São José do Rio Preto, São Paulo, Brazil
| | - Sidney J de Carvalho
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Rua Cristovão Colombo 2265, Jd. Nazareth, 15054-000, São José do Rio Preto, São Paulo, Brazil.
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33
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Posel Z, Svoboda M, Colina CM, Lísal M. Flow and aggregation of rod-like proteins in slit and cylindrical pores coated with polymer brushes: an insight from dissipative particle dynamics. SOFT MATTER 2017; 13:1634-1645. [PMID: 28133676 DOI: 10.1039/c6sm02751b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We use a meso-scale dissipative particle dynamics method to simulate the flow and aggregation of rod-like protein solutions through pores grafted with a solvent-sensitive polymer brush. The coated pores can control protein permeability and aggregation by a stretch-to-collapse conformational transition of the brush polymers in response to changes in the solvent quality. The protein solutions mimic aqueous glycoprotein solutions and proteins are represented as rod-like objects formed by coarse-grain beads. The model further employs two types of beads to represent the existence of cystein-like terminal groups in real glycoproteins and mimic the aggregation of real glycoproteins in aqueous solutions. We vary the solvent quality with respect to the brush chains and study the flow and aggregation of rod-like proteins in the slit and cylindrical pores as the brush polymers undergo the stretch-to-collapse transition. The results show that stretched brush chains close the pore, hamper proteins' flow and promote proteins' aggregation. The collapsed brush chains open the pores for proteins' flow and suppress their aggregation. Therefore, we observe more than a ten-fold reduction in the permeation rate of proteins in both pore geometries. Finally, due to pore confinement, larger proteins' aggregates are formed in the slit pore than in the cylindrical pore, while more pronounced orientation of proteins in the flow direction is seen in the cylindrical pore than in the slit pore.
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Affiliation(s)
- Zbyšek Posel
- Department of Informatics, Faculty of Science, J. E. Purkinje University, Ústí n. Lab., Czech Republic. and Laboratory of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Prague, Czech Republic
| | - Martin Svoboda
- Laboratory of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Prague, Czech Republic and Department of Physics, Faculty of Science, J. E. Purkinje University, Ústí n. Lab., Czech Republic
| | - Coray M Colina
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Martin Lísal
- Laboratory of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Prague, Czech Republic and Department of Physics, Faculty of Science, J. E. Purkinje University, Ústí n. Lab., Czech Republic
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Adroher-Benítez I, Martín-Molina A, Ahualli S, Quesada-Pérez M, Odriozola G, Moncho-Jordá A. Competition between excluded-volume and electrostatic interactions for nanogel swelling: effects of the counterion valence and nanogel charge. Phys Chem Chem Phys 2017; 19:6838-6848. [DOI: 10.1039/c6cp08683g] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The equilibrium distribution of monovalent and trivalent ions within a thermo-responsive charged nanogel is investigated using Monte Carlo simulations and Ornstein–Zernike equations.
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Affiliation(s)
- Irene Adroher-Benítez
- Departamento de Física Aplicada
- Facultad de Ciencias
- Universidad de Granada
- 18001 Granada
- Spain
| | - Alberto Martín-Molina
- Departamento de Física Aplicada
- Facultad de Ciencias
- Universidad de Granada
- 18001 Granada
- Spain
| | - Silvia Ahualli
- Departamento de Física Aplicada
- Facultad de Ciencias
- Universidad de Granada
- 18001 Granada
- Spain
| | - Manuel Quesada-Pérez
- Departamento de Física
- Escuela Politécnica Superior de Linares
- Universidad de Jaeén
- 23700 Linares
- Spain
| | - Gerardo Odriozola
- Área de Física de Procesos Irreversibles
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana
- 02200 México CD de México
- Mexico
| | - Arturo Moncho-Jordá
- Departamento de Física Aplicada
- Facultad de Ciencias
- Universidad de Granada
- 18001 Granada
- Spain
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Brilliantov NV, Budkov YA, Seidel C. Generation of mechanical force by grafted polyelectrolytes in an electric field: application to polyelectrolyte-based nano-devices. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2016.0143. [PMID: 27698040 DOI: 10.1098/rsta.2016.0143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/01/2016] [Indexed: 05/27/2023]
Abstract
We analyse theoretically and by means of molecular dynamics (MD) simulations the generation of mechanical force by a polyelectrolyte (PE) chain grafted to a plane. The PE is exposed to an external electric field that favours its adsorption on the plane. The free end of the chain is linked to a deformable target body. By varying the field, one can alter the length of the non-adsorbed part of the chain. This entails variation of the deformation of the target body and hence variation of the force arising in the body. Our theoretical predictions for the generated force are in very good agreement with the MD data. Using the theory developed for the generated force, we study the effectiveness of possible PE-based nano-vices, composed of two clenching planes connected by PEs and exposed to an external electric field. We exploit the Cundall-Strack solid friction model to describe the friction between a particle and the clenching planes. We compute the diffusion coefficient of a clenched particle and show that it drastically decreases even in weak applied fields. This demonstrates the efficacy of the PE-based nano-vices, which may be a possible alternative to the existing nanotube nano-tweezers and optical tweezers.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.
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Affiliation(s)
- N V Brilliantov
- Department of Mathematics, University of Leicester, Leicester LE1 7RH, UK
| | - Yu A Budkov
- National Research University Higher School of Economics, Department of Applied Mathematics, Moscow, Russia
| | - C Seidel
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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Capillary rise dynamics of liquid hydrocarbons in mesoporous silica as explored by gravimetry, optical and neutron imaging: Nano-rheology and determination of pore size distributions from the shape of imbibition fronts. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2015.09.055] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Hofmann T, Wallacher D, Perlich J, Koyiloth Vayalil S, Huber P. Formation of Periodically Arranged Nanobubbles in Mesopores: Capillary Bridge Formation and Cavitation during Sorption and Solidification in an Hierarchical Porous SBA-15 Matrix. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2928-2936. [PMID: 26940230 DOI: 10.1021/acs.langmuir.5b04560] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report synchrotron-based small-angle X-ray scattering experiments on a template-grown porous silica matrix (Santa Barbara Amorphous-15) upon in situ sorption of fluorinated pentane C5F12 along with volumetric gas sorption isotherm measurements. Within the mean-field model of Saam and Cole for vapor condensation in cylindrical pores, a nitrogen and C5F12 sorption isotherm is well described by a bimodal pore radius distribution dominated by meso- and micropores with 3.4 and 1.6 nm mean radius, respectively. In the scattering experiments, two different periodicities become evident. One of them (d1 = 11.5 nm) reflects the next nearest neighbor distance in a 2D-hexagonal lattice of tubular mesopores. A second periodicity (d2 = 11.4 nm) found during in situ sorption and freezing experiments is traced back to a superstructure along the cylindrical mesopores. It is compatible with periodic pore corrugations found in electron tomograms of empty SBA-15 by Gommes et al. ( Chem. Mater. 2009, 21, 1311 - 1317). A Rayleigh-Plateau instability occurring at the cylindrical blockcopolymer micelles characteristic of the SBA-15 templating process quantitatively accounts for the superstructure and thus the spatial periodicity of the pore wall corrugation. The consequences of this peculiar morphological feature on the spatial arrangement of C5F12, in particular the formation of periodically arranged nanobubbles (or voids) upon adsorption, desorption, and freezing of liquids, are discussed in terms of capillary bridge formation and cavitation in tubular but periodically corrugated pores.
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Affiliation(s)
- Tommy Hofmann
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , D-12489 Berlin, Germany
| | - Dirk Wallacher
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , D-12489 Berlin, Germany
| | - Jan Perlich
- Deutsches Elektronen Synchrotron , D-22607 Hamburg, Germany
| | | | - Patrick Huber
- Technische Universität Hamburg , D-21073 Hamburg, Germany
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38
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Luque-Caballero G, Maldonado-Valderrama J, Quesada-Pérez M, Martín-Molina A. Atomic force microscopy as a tool to study the adsorption of DNA onto lipid interfaces. Microsc Res Tech 2016; 80:11-17. [PMID: 27014963 DOI: 10.1002/jemt.22654] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/25/2016] [Accepted: 02/05/2016] [Indexed: 11/08/2022]
Abstract
The Atomic Force Microscopy (AFM) technique appears as a central tool for the characterization of DNA adsorption onto lipid interfaces. Regardless of the huge number of surveys devoted to this issue, there are still fascinating phenomena in this field that have not been explored in detail by AFM. For instance, adsorption of DNA onto like-charged lipid surfaces mediated by cations is still not fully understood even though it is gaining popularity nowadays in gene therapy and nanotechnology. Studies related to the complexation of DNA with anionic lipids as a non-viral gene delivery vehicle as well as the formation of self-assembled nanoscale DNA constructs (DNA origami) are two of the most attractive systems. Unfortunately, molecular mechanisms underlying the adsorption of DNA onto anionic lipid interfaces remain unclear so far. In view of that, AFM becomes an appropriate technique to provide valuable information to understand the adsorption of DNA to anionic lipid surfaces. As a second part of this review we provide an illustrative example of application of the AFM technique to probe the DNA adsorption onto a model lipid monolayer negatively charged. Microsc. Res. Tech. 80:11-17, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Germán Luque-Caballero
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, Granada, 18071, Spain
| | - Julia Maldonado-Valderrama
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, Granada, 18071, Spain
| | - Manuel Quesada-Pérez
- Departamento de Física, Escuela Politécnica Superior de Linares, Universidad de Jaén, Linares, Jaén, 23700, Spain
| | - Alberto Martín-Molina
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, Granada, 18071, Spain
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Rouster P, Pavlovic M, Szilagyi I. Improving the stability of titania nanosheets by functionalization with polyelectrolytes. RSC Adv 2016. [DOI: 10.1039/c6ra23707j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Highly stable suspensions of titanate nanosheets were designed by surface functionalization with P(AAm-co-DADMAC) copolymer.
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Affiliation(s)
- Paul Rouster
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1205 Geneva
- Switzerland
| | - Marko Pavlovic
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1205 Geneva
- Switzerland
| | - Istvan Szilagyi
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1205 Geneva
- Switzerland
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40
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Salt-induced reentrant stability of polyion-decorated particles with tunable surface charge density. Colloids Surf B Biointerfaces 2016; 137:109-20. [DOI: 10.1016/j.colsurfb.2015.06.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 01/17/2023]
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Gross J, Vogel T, Bachmann M. Structural phases of adsorption for flexible polymers on nanocylinder surfaces. Phys Chem Chem Phys 2015; 17:30702-11. [PMID: 26526935 DOI: 10.1039/c5cp03952e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
By means of generalized-ensemble Monte Carlo simulations, we investigate the thermodynamic behavior of a flexible, elastic polymer model in the presence of an attractive nanocylinder. We systematically identify the structural phases that are formed by competing monomer-monomer and monomer-substrate interactions. The influence of the relative surface attraction strength on the structural phases in the hyperphase diagram, parameterized by cylinder radius and temperature, is discussed as well. In the limiting case of the infinitely large cylinder radius, our results coincide with previous outcomes of studies of polymer adsorption on planar substrates.
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Affiliation(s)
- Jonathan Gross
- Soft Matter Systems Research Group, Center for Simulational Physics, The University of Georgia, Athens, GA 30602, USA. and Institut für Theoretische Physik and Centre for Theoretical Sciences (NTZ), Universität Leipzig, Postfach 100 920, D-04009 Leipzig, Germany.
| | - Thomas Vogel
- Department of Physics, Stetson University, DeLand, FL 32723, USA and Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | - Michael Bachmann
- Soft Matter Systems Research Group, Center for Simulational Physics, The University of Georgia, Athens, GA 30602, USA. and Instituto de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, Mato Grosso, Brazil
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Song W, Liu L, Liu G. Ion specificity of macromolecules in crowded environments. SOFT MATTER 2015; 11:5940-5946. [PMID: 26119620 DOI: 10.1039/c5sm01023c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Macromolecular crowding plays a significant role in the solubility and stability of biomacromolecules. In this work, the thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) has been employed as a model system to study the specific ion effects on the solubility of macromolecules in crowded environments of dextran and polyethylene glycol (PEG). Our study demonstrates that crowding agents can interact with either anions or PNIPAM chains. The chaotropic anion SCN(-) interacts with dextran but does not interact with PEG. Both Cl(-) and CH3COO(-) do not interact with dextran and PEG. On the other hand, dextran can interact with PNIPAM as a hydrogen-bond donor, whereas PEG interacts with PNIPAM as a hydrogen-bond acceptor. The salting-in effect exerted by SCN(-) on PNIPAM is weakened in the crowded environment of dextran but is strengthened in the crowded environment of PEG due to the distinct anion-crowder interactions. In parallel, the salting-out effect generated by Cl(-) and CH3COO(-) on PNIPAM is weakened by the crowding of dextran but is strengthened by the crowding of PEG because of the different macromolecule-crowder interactions. Our study reveals that the ion specificity of macromolecules is altered significantly changing from dilute solutions to crowded environments.
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Affiliation(s)
- Wangqin Song
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
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Vázquez-Montejo P, McDargh Z, Deserno M, Guven J. Cylindrical confinement of semiflexible polymers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:063203. [PMID: 26172814 DOI: 10.1103/physreve.91.063203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Indexed: 06/04/2023]
Abstract
Equilibrium states of a closed semiflexible polymer binding to a cylinder are described. This may be either by confinement or by constriction. Closed completely bound states are labeled by two integers: the number of oscillations, n, and the number of times it winds the cylinder, p, the latter being a topological invariant. We examine the behavior of these states as the length of the loop is increased by evaluating the energy, the conserved axial torque, and the contact force. The ground state for a given p is the state with n=1; a short loop with p=1 is an elliptic deformation of a parallel circle; as its length increases it elongates along the cylinder axis with two hairpin ends. Excited states with n≥2 and p=1 possess n-fold axial symmetry. Short (long) loops possess energies ≈pE(0)(nE(0)), with E(0) the energy of a circular loop with same radius as the cylinder; in long loops the axial torque vanishes. Confined bound excited states are initially unstable; however, above a critical length each n-fold state becomes stable: The folded hairpin cannot be unfolded. The ground state for each p is also initially unstable with respect to deformations rotating the loop off the surface into the interior. A closed planar elastic curve aligned along the cylinder axis making contact with the cylinder on its two sides is identified as the ground state of a confined loop. Exterior bound states behave very differently, if free to unbind, as signaled by the reversal in the sign of the contact force. If p=1, all such states are unstable. If p≥2, however, a topological obstruction to complete unbinding exists. If the loop is short, the bound state with p=2 and n=1 provides a stable constriction of the cylinder, partially unbinding as the length is increased. This motif could be relevant to an understanding of the process of membrane fission mediated by dynamin rings.
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Affiliation(s)
- Pablo Vázquez-Montejo
- Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA
| | - Zachary McDargh
- Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA
| | - Jemal Guven
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México Apartado Postal 70-543, 04510 México, Distrito Federal, Mexico
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