title: Structural properties of oligonucleotide monolayers on gold surfaces probed by fluorescence investigations.
abstract: We present optical investigations on the conformation of oligonucleotide layers on Au surfaces. Our studies concentrate on the effect of varying surface coverage densities on the structural properties of layers of 12- and 24mer single-stranded DNA, tethered to the Au surface at one end while being labeled with a fluorescent marker at the opposing end. The distance-dependent energy transfer from the marker dye to the metal surface, which causes quenching of the observed fluorescence, is used to provide information on the orientation of the DNA strands relative to the surface. Variations in the oligonucleotide coverage density, as determined from electrochemical quantification, over 2 orders of magnitude are achieved by employing different preparation conditions. The observed enhancement in fluorescence intensity with increasing DNA coverage can be related to a model involving mutual steric interactions of oligonucleotides on the surface, as well as fluorescence quenching theory. Finally, the applicability of the presented concepts for investigations of heterogeneous monolayers is demonstrated by means of studying the coadsorption of mercaptohexanol onto DNA-modified Au surfaces.
authors.affiliation: Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, 85748 Garching, Germany. rant@wsi.tum.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Rant
authors.forename: Kenji
authors.initials: K
authors.lastname: Arinaga
authors.forename: Shozo
authors.initials: S
authors.lastname: Fujita
authors.forename: Naoki
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Gerhard
authors.initials: G
authors.lastname: Abstreiter
authors.forename: Marc
authors.initials: M
authors.lastname: Tornow
mesh_terms: D004247:DNA / Q000737:chemistry; D004735:Energy Transfer; D005456:Fluorescent Dyes; D006046:Gold; D008567:Membranes, Artificial; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013499:Surface Properties
chemical_list: D005456:Fluorescent Dyes; D008567:Membranes, Artificial; D009838:Oligodeoxyribonucleotides; D006046:Gold; D004247:DNA