Direct imaging of hexaamine-ruthenium(III) in domain boundaries in monolayers of single-stranded DNA.
We describe adsorption and identification of the binding sites of [Ru(NH3)6]3+ (RuHex) molecules in a closely packed monolayer of a 13-base ss-DNA on Au(111) electrodes by electrochemical in situ scanning tunneling microscopy (STM), cyclic voltammetry and interfacial capacitance data. In situ STM at single-molecule resolution shows that RuHex adsorbs only at the domain borders and near defects. Together with the electrochemical data that show a negative redox potential shift for RuHex adsorbed to DNA strands, this strongly suggests that RuHex binds only to the exposed phosphate groups in the DNA backbone.
Grubb
Mikala
M
Department of Chemistry, Nano DTU, Technical University of Denmark, Building 207, DK-2800 Kgs. Lyngby, Denmark.
Wackerbarth
Hainer
H
Wengel
Jesper
J
Ulstrup
Jens
J
D000327:Adsorption; D001665:Binding Sites; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism*; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold; D016252:Microscopy, Scanning Tunneling; D009838:Oligodeoxyribonucleotides; D017975:Ruthenium Compounds / Q000737:chemistry*
D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides; D017975:Ruthenium Compounds; D006046:Gold