Electrochemistry and in situ scanning tunnelling microscopy of pure and redox-marked DNA- and UNA-based oligonucleotides on Au(111)-electrode surfaces

摘要: We have studied adsorption and electrochemical electron transfer of several 13- 15-base DNA UNA (unlocked nucleic acids) oligonucleotides (ONs) linked to Au(111)-electrode surfaces via a 5′-C6-SH group using cyclic voltammetry (CV) scanning tunnelling microscopy in aqueous buffer under potential control (in situ STM). 2,2′,6′,2′′-Terpyridine (terpy) onto which the transition metal ions Fe2+/3+, Os2+/3+ Ru2+/3+ could be coordinated after monolayer formation was attached flexible linker. The centres offer CV probes STM contrast markers, UNA/linker binder for intercalation. pure mercaptohexanol diluted ON monolayers displayed reductive desorption signals but also, presumably capacitive, at higher potentials. Distinct voltammetric arise on binding. Those from Ru-binding are by far strongest accord with multiple site Ru-attachment. In disclosed molecular scale features varying coverage addition ions. Ru-derivatives showed bias voltage dependent broad maximum current–overpotential correlation correlated theoretical frames condensed matter conductivity redox molecules. Together data suggest that Ru-units bound both terpy UNA–DNA backbone.