AI Article Synopsis
- Filamentous polyelectrolytes, like the Pf1 virus, can aggregate into bundles due to interactions with multivalent counterions, leading to the formation of a gel phase even at low concentrations.
- The gelation of Pf1 can occur at just 0.04% volume fraction, significantly lower than the 0.7% required for the transition from isotropic to nematic phases in solutions with monovalent salt.
- Unlike traditional strong gels that stiffen under strain, Pf1 gels exhibit a unique behavior of softening at high strain, with this softening occurring based on how strongly the counterions interact with the polyelectrolyte.
Article Abstract
Filamentous polyelectrolytes in aqueous solution aggregate into bundles by interactions with multivalent counterions. These effects are well documented by experiment and theory. Theories also predict a gel phase in isotropic rodlike polyelectrolyte solutions caused by multivalent counterion concentrations much lower than those required for filament bundling. We report here the gelation of Pf1 virus, a model semiflexible polyelectrolyte, by the counterions Mg(2+), Mn(2+) and spermine(4+). Gelation can occur at 0.04% Pf1 volume fraction, which is far below the isotropic-nematic transition of 0.7% for Pf1 in monovalent salt. Unlike strongly crosslinked gels of semiflexible polymers, which stiffen at large strains, Pf1 gels reversibly soften at high strain. The onset strain for softening depends on the strength of interaction between counterions and the polyelectrolyte. Simulations show that the elasticity of counterion crosslinked gels is consistent with a model of semiflexible filaments held by weak crosslinks that reversibly rupture at a critical force.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262026 | PMC |
| http://dx.doi.org/10.1039/C1SM05553D | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Angstrom Scale Ionic Memristors' Engineering with van der Waals Materials: A Route to Highly Tunable Memory States.
ACS Appl Mater Interfaces
December 2024
Department of Physics, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India.
Memristors that mimic brain functions are crucial for energy-efficient neuromorphic devices. Ion channels that emulate biological synapses are still in the early stages of development, especially the tunability of memory states. Here, we demonstrate that cations such as K, Na, Ca, and Al intercalated in the interlayer spaces of vermiculite result in highly confined channels of size 3-5 Å.
View Article and Find Full Text PDFA review on salt-induced DNA compaction and charge inversion.
Prog Biophys Mol Biol
November 2024
Department of Physics, Prithvinarayan Campus, Tribhuvan University, Pokhara, Nepal. Electronic address:
This review delves into the reversible process of DNA compaction, vital for cellular functions like replication and transcription. The study highlights how various cations assist in the condensation of DNA chains, highlighting their specificity. The impact of the ionic environment on chromatin characteristics is discussed, emphasizing the roles of mono- and divalent cations in neutralizing DNA charge and promoting compaction.
View Article and Find Full Text PDFAdsorption of polyelectrolytes in the presence of varying dielectric discontinuity between solution and substrate.
J Chem Phys
October 2024
Department of Applied Physics, Aalto University, P.O. Box 15600, FI-00076 Aalto, Finland.
We examine the interactions between polyelectrolytes (PEs) and uncharged substrates under conditions corresponding to a dielectric discontinuity between the aqueous solution and the substrate. To this end, we vary the relevant system characteristics, in particular the substrate dielectric constant ɛs under different salt conditions. We employ coarse-grained molecular dynamics simulations with rodlike PEs in salt solutions with explicit ions and implicit water solvent with dielectric constant ɛw = 80.
View Article and Find Full Text PDFCharge regulation of nanoparticles in the presence of multivalent electrolytes.
J Chem Phys
September 2024
Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil.
We explore the charge regulation (CR) of spherical nanoparticles immersed in an asymmetric electrolyte of a specified pH. Using a recently developed reactive canonical Monte Carlo (MC) simulation method, titration isotherms are obtained for suspensions containing monovalent, divalent, and trivalent coions. A theory based on the modified Poisson-Boltzmann approximation, which incorporates the electrostatic ion solvation free energy and discrete surface charge effects, is used to compare with the simulation results.
View Article and Find Full Text PDFQuantitative measurement of cation-mediated adhesion of DNA to anionic surfaces.
Soft Matter
September 2024
Department of Chemistry and Biochemistry, School of Natural Sciences, University of California, Merced, California 95343, USA.
Anionic polyelectrolytes, such as DNA, are attracted to anionic surfaces in the presence of multivalent cations. A major barrier toward molecular-level understanding of these attractive interactions is the paucity of measurements of the binding strength. Here, atomic force microscopy-based single molecule force spectroscopy was used to quantify the binding free energy of double-stranded DNA to an anionic surface, with complementary density functional theory calculations of the binding energies of metal ion-ligand complexes.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!