title: Polymer- and salt-induced toroids of hexagonal DNA.
abstract: A model is proposed for polymer- and salt-induced toroidal condensates of DNA, based on a recent theory of the undulation enhancement of the electrostatic interaction in the bulk hexagonal phase of semiflexible polyions. In a continuum approximation, the thermodynamic potential of a monomolecular toroid may be split up in bulk, surface, and curvature contributions. With the help of an approximate analytical minimization procedure, the optimal torus dimensions are calculated as a function of the concentrations of inert polymer and added salt. The stability of the torus is analyzed in terms of its surface tension and a bulk melting criterion. The theory should be applicable to psi-toroids that are not too thick.
authors.affiliation: Department of Polymer Technology, Faculty of Chemical Engineering and Materials Science, Delft University of Technology, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Ubbink
authors.forename: T
authors.initials: T
authors.lastname: Odijk
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004247:DNA / Q000737:chemistry*; D004270:DNA, Circular / Q000737:chemistry; D004563:Electrochemistry; D008956:Models, Chemical; D009690:Nucleic Acid Conformation; D011108:Polymers; D012965:Sodium Chloride; D012996:Solutions; D013816:Thermodynamics
chemical_list: D004270:DNA, Circular; D011108:Polymers; D012996:Solutions; D012965:Sodium Chloride; D004247:DNA