Abstract
Alkanethiols self-assemble into monolayers on gold surfaces. It has been shown that gold surfaces derivatized with two-carbon, bifunctional alkanethiols differentially adsorb DNA. Gold surfaces modified with either 2-(N,N-dimethylamino)ethanethiol or 2-aminoethanethiol immobilize DNA at solution pH's where the amino end groups are protonated. The cationic layer holds the DNA in place by ion-pairing with the negatively-charged phosphate groups on the DNA backbone. This ion-pairing is sufficiently strong to resist changes in the DNA's location and conformation induced by the scanning tunneling microscope (STM) tip. With these chemically modified surfaces, the reliable and reproducible imaging of DNA is possible. When the length of the alkane spacer is increased to eleven carbons, the observed affinities for radiolabeled DNA are comparable to that observed for the two carbon spacer. However, clearly resolved STM images of DNA immobilized on 11-(N,N'-dimethylamino)-undecanethiol-modified gold have not been obtainable. We hypothesize that images of immobilized DNA are not observed because of the interaction of the scanning probe with the self-assembled alkanethiol monolayer.
Original language | English |
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Pages (from-to) | 48-55 |
Number of pages | 8 |
Journal | Proceedings of SPIE - The International Society for Optical Engineering |
Volume | 1891 |
DOIs | |
State | Published - Jun 24 1993 |
Externally published | Yes |
Event | Advances in DNA Sequencing Technology 1993 - Los Angeles, United States Duration: Jan 17 1993 → Jan 22 1993 |
Funding
We express our gratitude to Rick Woychik and J. J. Schrick of the Biology Division at ORNL for the preparation of the radiolabeled plasinid sample. The support of this research by the Bristol-Myers-Squibb Corporation through a Research Opportunities Award to L.A.B. by The Research Corporation and by the Office of Health and Environmental Research, U.S. Department ofEnergy, under Contract No. DE-ACO5-84OR21400 with Martin Marietta Energy Systems, Inc. is gratefully acknowledged. The support of this research by the Bristol-Myers-Squibb Corporation through a Research Opportunities Award to L.A.B. by The Research Corporation and by the Office of Health and Environmental Research, U.S. Department of Energy, under Contract No. DE-ACO5-84OR21400 with Martin Marietta Energy Systems, Inc. is gratefully acknowledged
Funders | Funder number |
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Bristol-Myers-Squibb Corporation | |
Office of Health and Environmental Research | |
Research | |
U.S. Department ofEnergy | |
U.S. Department of Energy | DE-ACO5-84OR21400 |
Research Corporation for Science Advancement |