title: Real-space transmission electron microscopy investigations of attachment of functionalized magnetic nanoparticles to DNA-coils acting as a biosensor.
abstract: The present work provides the first real-space analysis of nanobead-DNA coil interactions. Immobilization of oligonucleotide-functionalized magnetic nanobeads in rolling circle amplified DNA-coils was studied by complex magnetization measurements and transmission electron microscopy (TEM), and a statistical analysis of the number of beads hybridized to the DNA-coils was performed. The average number of beads per DNA-coil using the results from both methods was found to be around 6 and slightly above 2 for samples with 40 and 130 nm beads, respectively. The TEM analysis supported an earlier hypothesis that 40 nm beads are preferably immobilized in the interior of DNA-coils whereas 130 nm beads, to a larger extent, are immobilized closer to the exterior of the coils. The methodology demonstrated in the present work should open up new possibilities for characterization of interactions of a large variety of functionalized nanoparticles with macromolecules, useful for gaining more fundamental understanding of such interactions as well as for optimizing a number of biosensor applications.
authors.affiliation: Department of Engineering Sciences, Division of Electron Microscopy and Nanoengineering, The Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Sultan
authors.initials: S
authors.lastname: Akhtar
authors.forename: Mattias
authors.initials: M
authors.lastname: Strömberg
authors.forename: Teresa
authors.initials: T
authors.lastname: Zardán Gómez de la Torre
authors.forename: Camilla
authors.initials: C
authors.lastname: Russell
authors.forename: Klas
authors.initials: K
authors.lastname: Gunnarsson
authors.forename: Mats
authors.initials: M
authors.lastname: Nilsson
authors.forename: Peter
authors.initials: P
authors.lastname: Svedlindh
authors.forename: Maria
authors.initials: M
authors.lastname: Strømme
authors.forename: Klaus
authors.initials: K
authors.lastname: Leifer
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D004247:DNA / Q000737:chemistry*; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*
chemical_list: D004247:DNA