title: Statistical mechanics of DNA-mediated colloidal aggregation.
abstract: We present a statistical mechanical model of aggregation in colloidal systems with DNA-mediated interactions. We obtain a general result for the two-particle binding energy in terms of the hybridization free energy DeltaG of DNA and two model-dependent properties: the average number of available DNA bridges <N> and the effective DNA concentration c(eff). We calculate these parameters for a particular DNA bridging scheme. The fraction of all the n-mers, including the infinite aggregate, are shown to be universal functions of a single parameter directly related to the two-particle binding energy. We explicitly take into account the partial ergodicity of the problem resulting from the slow DNA binding-unbinding dynamics, and introduce the concept of angular localization of DNA linkers. In this way, we obtain a direct link between DNA thermodynamics and the global aggregation and melting properties in DNA-colloidal systems. The results of the theory are shown to be in quantitative agreement with two recent experiments with particles of micron and nanometer size.
authors.affiliation: Department of Physics and Michigan Center for Theoretical Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Licata
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Tkachenko
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D019563:Mechanics; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009690:Nucleic Acid Conformation; D011789:Quantum Theory
chemical_list: D003102:Colloids; D004247:DNA