title: Entropic attraction: Polymer compaction and expansion induced by nano-particles in confinement.
abstract: We investigated nanoparticle (NP)-induced coil-to-globule transition of a semi-flexible polymer in a confined suspension of ideal NP using Langevin dynamics. DNA molecules are often found to be highly compact, bound with oppositely charged proteins in a crowded environment within cells and viruses. Recent studies found that high concentration of electrostatically neutral NP also condenses DNA due to entropically induced depletion attraction between DNA segments. Langevin dynamics simulations with a semi-flexible chain under strong confinement were performed to investigate the competition between NP-induced monomer-monomer and monomer-wall attraction under different confinement heights and NP volume fractions. We found that whether NP induce polymer segments to adsorb to the walls and swell or to attract one another and compact strongly depends on the relative strength of the monomer-wall and the NP-wall interactions.
authors.affiliation: Department of Physics, National Taiwan University, Taipei, Taiwan.
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Liao
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Fan-Tso
authors.initials: FT
authors.lastname: Chien
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Dmytro
authors.initials: D
authors.lastname: Luzhbin
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Yeng-Long
authors.initials: YL
authors.lastname: Chen
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000737:chemistry; D004548:Elasticity; D019277:Entropy; D008956:Models, Chemical; D053758:Nanoparticles / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D011108:Polymers / Q000737:chemistry*; D012996:Solutions; D055672:Static Electricity; D013535:Suspensions
chemical_list: D011108:Polymers; D012996:Solutions; D013535:Suspensions; D004247:DNA