Scanning Tunneling Microscopy and Spectroscopy of Plasmid DNA

Authors

D. P. Allison, Oak Ridge National Laboratory
J. R. Thompson, Oak Ridge National Laboratory
K. Bruce Jacobson, Oak Ridge National Laboratory
R. J. Warmack, University of Tennessee
T. L. Ferrell, University of Tennessee

Abstract

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 de 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.

Recommended Citation

Allison, D. P.; Thompson, J. R.; Jacobson, K. Bruce; Warmack, R. J.; and Ferrell, T. L. (1990) "Scanning Tunneling Microscopy and Spectroscopy of Plasmid DNA," Scanning Microscopy: Vol. 4: No. 3, Article 2.
Available at: https://digitalcommons.usu.edu/microscopy/vol4/iss3/2