title: Identification of single-strand DNA by in situ scanning tunneling microscopy.
abstract: We report here in situ scanning tunneling microscopy imaging of hexaammineruthenium (II)/(III) (RuHex) binding to single-strand DNA oligonucleotide with 13 bases immobilized in a mixed monolayer on a single-crystal Au(111) surface. RuHex does not bind to the other component in the monolayer, mercaptohexanol. Images before and after addition of RuHex show a strong contrast increase, suggesting that single-stranded DNA is, indeed, conducting when a redox group is bound to the strand. When compared with previous results, the data also suggest that the mechanism of domain formation of the immobilized DNA is independent of the sequence.
authors.affiliation: Bioinorganic Group, Department of Chemistry and NanoDTU, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Mikala
authors.initials: M
authors.lastname: Grubb
authors.forename: Hainer
authors.initials: H
authors.lastname: Wackerbarth
authors.forename: Jens
authors.initials: J
authors.lastname: Ulstrup
mesh_terms: D000327:Adsorption; D001483:Base Sequence; D002021:Buffers; D004247:DNA / Q000032:analysis* / Q000737:chemistry*; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry*; D000441:Hexanols / Q000737:chemistry; D016252:Microscopy, Scanning Tunneling; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D017975:Ruthenium Compounds / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D002021:Buffers; D000441:Hexanols; D017975:Ruthenium Compounds; D013438:Sulfhydryl Compounds; C031584:hexammineruthenium; D006046:Gold; D004247:DNA; C477019:3-mercaptohexanol