title: Shape Analysis of DNA-Au Hybrid Particles by Analytical Ultracentrifugation.
abstract: Current developments in nanotechnology have increased the demand for nanocrystal assemblies with well-defined shapes and tunable sizes. DNA is a particularly well-suited building block in nanoscale assemblies because of its scalable sizes, conformational variability, and convenient self-assembly capabilities via base pairing. In hybrid materials, gold nanoparticles (AuNPs) can be assembled into nanoparticle structures with programmable interparticle distances by applying appropriate DNA sequences. However, the development of stoichiometrically defined DNA/NP structures is still challenging since product mixtures are frequently obtained and their purification and characterization is the rate-limiting step in the development of DNA-NP hybrid assemblies. Improvements in nanostructure fractionation and characterization techniques offer great potential for nanotechnology applications in general. This study reports the application of analytical ultracentrifugation (AUC) for the characterization of anisotropic DNA-linked metal-crystal assemblies. On the basis of transmission electron microscopy data and the DNA primary sequence, hydrodynamic bead models are set up for the interpretation of the measured frictional ratios and sedimentation coefficients. We demonstrate that the presence of single DNA strands on particle surfaces as well as the shape factors of multiparticle structures in mixtures can be quantitatively described by AUC. This study will significantly broaden the possibilities to analyze mixtures of shape-anisotropic nanoparticle assemblies. By establishing insights into the analysis of nanostructure mixtures based on fundamental principles of sedimentation, a wide range of potential applications in basic research and industry become accessible.
authors.affiliation: Department of Chemistry, University of Konstanz , Universitätsstr. 10, 78457 Konstanz, Germany.
authors.forename: Maximilan J
authors.initials: MJ
authors.lastname: Urban
authors.affiliation: Department of Chemistry, University of Konstanz , Universitätsstr. 10, 78457 Konstanz, Germany.
authors.forename: Isabelle T
authors.initials: IT
authors.lastname: Holder
authors.affiliation: Department of Chemistry, University of Konstanz , Universitätsstr. 10, 78457 Konstanz, Germany.
authors.forename: Marius
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Department of Physical Chemistry, University of Murcia , 30071 Murcia, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Fernandez Espin
authors.affiliation: Department of Physical Chemistry, University of Murcia , 30071 Murcia, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Garcia de la Torre
authors.affiliation: Department of Chemistry, University of Konstanz , Universitätsstr. 10, 78457 Konstanz, Germany.
authors.forename: Jörg S
authors.initials: JS
authors.lastname: Hartig
authors.affiliation: Department of Chemistry, University of Konstanz , Universitätsstr. 10, 78457 Konstanz, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Cölfen
mesh_terms: D004247:DNA / Q000737:chemistry*; D006046:Gold; D053768:Metal Nanoparticles; D036103:Nanotechnology; D014461:Ultracentrifugation
chemical_list: D006046:Gold; D004247:DNA
keywords: analytical ultracentrifugation; anisotropic nanostructures; bead models; gold nanoparticle−DNA assembly; sedimentation velocity; self-assembly; shape analysis