Direct observation of bioelectrochemical processes by scanning tunneling microscopy

Stuart Lindsay, T. Thundat, L. A. Naaahara, P. Oden

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

We have imaged DNA deposits that have been reacted onto a gold electrode. Our scanning tunneling microscope (STM) is operated in a three electrode cell using insulated tips. Samples are deposited at a controlled potential relative to an Ag/AgCl reference electrode. Many different adsorption geometries are observed, different substrate potentials resulting in characteristic adsorption patterns. Here, we report initial results for negative electrodes. At — 2.3 V (Ag/ AgCl), the DNA appears to attach to the substrate end on. As the potential is lowered towards zero volts, the DNA attaches side on, forming aggregates of decreasing complexity with decreasing substrate potential. Isolated molecules are observed near — 1 V (Ag/AgCl). Below this potential, coverage is much less dense. Those molecules that adsorb do so in aggregates, which may bind in alignment with the underlying atomic structure of the substrate.

Original languageEnglish (US)
Pages (from-to)645-647
Number of pages3
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume8
Issue number1
DOIs
StatePublished - 1990

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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