title: Association temperature governs structure and apparent thermodynamics of DNA-gold nanoparticles.
abstract: Apparent thermodynamics of association of DNA-modified gold nanoparticles has been characterized by UV spectroscopy and dynamic light scattering (DLS). Extinction coefficients of unlabelled and DNA-labelled gold nanoparticles have been determined to permit quantitative analysis of the absorption measurements. In contrast to previous studies the associating gold nanoparticles were furnished with complementary oligonucleotide DNA single strands. This resulted in direct complex formation between the nanoparticles on mixing without the requirement of a DNA linker sequence for initiation of cluster formation. Melting curves of the nanoparticle assemblies formed at different temperatures were subjected to two-state analysis. A comparison of the apparent thermodynamic parameters obtained for the dissociation of these aggregates suggests that both thermodynamically and structurally different nanoparticle clusters are obtained depending on the temperature at which assembly proceeds. The van't Hoff enthalpies permit an estimate of the DNA duplexes: gold nanoparticle ratio involved in network formation.
authors.affiliation: Westfälische Wilhelms-Universität, Institut für Physikalische Chemie, Corrensstr. 30, 48149 Münster, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Beermann
authors.forename: Ernesto
authors.initials: E
authors.lastname: Carrillo-Nava
authors.forename: Andy
authors.initials: A
authors.lastname: Scheffer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Buscher
authors.forename: Anup M
authors.initials: AM
authors.lastname: Jawalekar
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Hinz
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D004277:DNA, Single-Stranded; D006046:Gold