Adsorption and surface dynamics of short DNA and LNA oligonucleotides on single-crystal Au(111) electrode surfaces

摘要

We have studied the surface dynamics of a double-stranded decanucleotide (HS-10AT(L)) with adenine-thymine base pairs linked to a Au(1 1 1)-electrode surface via a hexamethylene thiol linker. The study is based on a combination of voltammetry, interfacial capacitance data, electrochemical in situ scanning tunnelling microscopy, and X-ray photoelectron spectroscopy. The thymine bases of the oligonucleotide are connected to furanoses locked in C3'-endo configuration called LNA (locked nucleic acid). Hybridization in solution is effected prior to linking to the Au(1 1 1)-surface. The melting point of the linker-free locked decanucleotide, 10AT(L) is > 63 degrees C. However, voltammetric reductive desorption of the adsorbed thiol-modified double-strand decanucleotide, HS-10AT(L), gives almost the same charge as single-strand HS-10A, 29 +/- 3 and 27 +/- 5 mu C cm(-2), respectively. In situ STM after HS-10AT(L)-immobilization also gives images showing highly ordered domains, virtually indistinguishable from those of immobilized HS-10A. X-ray photoelectron spectroscopy gives an N/P ration of 5.0 for HS-10AT(L) in line with the expected value for single-strand HS-10A (5.0).