Scanning tunneling microscopy and spectroscopy of plasmid DNA

D. P. Allison, J. R. Thompson, K. B. Jacobson, R. J. Warmack, T. L. Ferrell

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We present scanning tunneling microscope (STM) images of uncoated deoxyribonucleic acid (DNA) electrochemically mounted on highly-oriented pyrolytic graphite (HOPG) and imaged in air. Images of linear abnormalities inherent to HOPG surfaces that can be confused with DNA are also presented. Scanning tunneling spectroscopic (STS) images generated by superimposing a small, high frequency ac bias onto the dc tunnel bias and recording the ac current signal were taken simultaneously with the topographic images. These spectroscopic images reveal contrast due to local conductivity variations and can be used to differentiate DNA molecules from graphite artifacts.

Original languageEnglish (US)
Pages (from-to)517-522
Number of pages6
JournalScanning Microscopy
Issue number3
StatePublished - 1990
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by JST Quantum Transition Project, ONR N00014-K-0692, and QUEST DMR91-20007. The authors are grateful to T. Ando, G.E.W. Bauer, A.B. Dzyubenko, A. Imamoglu, K. Johnsen for useful comments and discussions, and D.P. Enyeart, D.T. White and J.R. Allen at CTST for technical support.


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