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Title: Polymer crowding and shape distributions in polymer-nanoparticle mixtures

Abstract

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.

Authors:
;  [1]
  1. Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)
Publication Date:
OSTI Identifier:
22308414
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 141; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COMPUTERIZED SIMULATION; DNA; EIGENVALUES; FORECASTING; MONTE CARLO METHOD; POLYMERS; PROTEINS; RNA; SOLUTIONS; SOLVENTS

Citation Formats

Lim, Wei Kang, and Denton, Alan R., E-mail: alan.denton@ndsu.edu. Polymer crowding and shape distributions in polymer-nanoparticle mixtures. United States: N. p., 2014. Web. doi:10.1063/1.4895612.
Lim, Wei Kang, & Denton, Alan R., E-mail: alan.denton@ndsu.edu. Polymer crowding and shape distributions in polymer-nanoparticle mixtures. United States. doi:10.1063/1.4895612.
Lim, Wei Kang, and Denton, Alan R., E-mail: alan.denton@ndsu.edu. Sun . "Polymer crowding and shape distributions in polymer-nanoparticle mixtures". United States. doi:10.1063/1.4895612.
@article{osti_22308414,
title = {Polymer crowding and shape distributions in polymer-nanoparticle mixtures},
author = {Lim, Wei Kang and Denton, Alan R., E-mail: alan.denton@ndsu.edu},
abstractNote = {Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.},
doi = {10.1063/1.4895612},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 11,
volume = 141,
place = {United States},
year = {2014},
month = {9}
}