title: Small-angle neutron scattering and molecular dynamics structural study of gelling DNA nanostars.
abstract: DNA oligomers with properly designed sequences self-assemble into well defined constructs. Here, we exploit this methodology to produce bulk quantities of tetravalent DNA nanostars (each one composed of 196 nucleotides) and to explore the structural signatures of their aggregation process. We report small-angle neutron scattering experiments focused on the evaluation of both the form factor and the temperature evolution of the scattered intensity at a nanostar concentration where the system forms a tetravalent equilibrium gel. We also perform molecular dynamics simulations of one isolated tetramer to evaluate the form factor numerically, without resorting to any approximate shape. The numerical form factor is found to be in very good agreement with the experimental one. Simulations predict an essentially temperature-independent form factor, offering the possibility to extract the effective structure factor and its evolution during the equilibrium gelation.
authors: Sapienza-Università di Roma, P.le A. Moro 5, 00185 Roma, Italy.
authors: J
authors: J
authors: Fernandez-Castanon
authors: Sapienza-Università di Roma, P.le A. Moro 5, 00185 Roma, Italy.
authors: F
authors: F
authors: Bomboi
authors: Rudolf Peierls C.T.P., University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
authors: L
authors: L
authors: Rovigatti
authors: Dipartimento di Fisica, Università di Perugia, Via Pascoli, 06123 Perugia, Italy.
authors: M
authors: M
authors: Zanatta
authors: Dipartimento di Fisica, Università di Perugia, Via Pascoli, 06123 Perugia, Italy.
authors: A
authors: A
authors: Paciaroni
authors: Dipartimento di Fisica, Università di Perugia, Via Pascoli, 06123 Perugia, Italy.
authors: L
authors: L
authors: Comez
authors: Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France.
authors: L
authors: L
authors: Porcar
authors: Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors: C J
authors: CJ
authors: Jafta
authors: Laboratoire Léon Brillouin, LLB, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
authors: G C
authors: GC
authors: Fadda
authors: Department of Medical Biotechnology and Translational Medicine, Università di Milano, I-20133 Milano, Italy.
authors: T
authors: T
authors: Bellini
authors: Sapienza-Università di Roma, P.le A. Moro 5, 00185 Roma, Italy.
authors: F
authors: F
authors: Sciortino
mesh_terms: D004247:DNA / Q000737:chemistry*; D005163:Factor Analysis, Statistical; D005782:Gels / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D049329:Nanostructures / Q000737:chemistry*; D033363:Neutron Diffraction; D009690:Nucleic Acid Conformation; D053838:Scattering, Small Angle; D013696:Temperature
chemical_list: D005782:Gels; D004247:DNA