Title
Masking generates contiguous segments of metal-coated and bare DNA for scanning tunneling microscope imaging
Date Issued
15 August 1993
Access level
open access
Resource Type
journal article
Author(s)
Dunlap D.
García R.
Schabtach E.
University of Oregon
Publisher(s)
National Academy of Sciences
Abstract
To date, no microscopic methods are available to confirm scanning tunneling microscope (STM) images of DNA. The difficulties encountered in repeating these images may be attributed to inadequate distribution of molecules on the substrate, poor adhesion to the substrate, or the low conductivity of the molecules. However, these factors are difficult to assess in an STM experiment where they may act simultaneously. A method to isolate these factors involves partly masking the deposited molecules before coating them with a conductive film to produce adjacent segments of coated and bare DNA after the mask is removed. The coated DNA segments are conductive and mechanically stable to allow easy identification of DNA by the STM. Furthermore, the path of a molecule can be traced from a coated to an uncoated region to test STM imaging of bare DNA. Masked preparations of DNA deposited on platinum/carbon-coated mica and highly oriented pyrolytic graphite were examined with a tunneling current 1000 times lower than the usual nanoamps. The tip apparently displaces molecules adsorbed to graphite to preclude imaging whereas more stably bound DNA on platinum/carbon-coated mica appears in reversed contrast.
Start page
7652
End page
7655
Volume
90
Issue
16
Language
English
OCDE Knowledge area
Bioquímica, Biología molecular Biología celular, Microbiología
Scopus EID
2-s2.0-0027268218
PubMed ID
Source
Proceedings of the National Academy of Sciences of the United States of America
ISSN of the container
00278424
Sponsor(s)
National Institute of General Medical Sciences - R37GM032543.
Sources of information: Directorio de Producción Científica Scopus