Nanometer-Scale Force Profiles of Short Single- And Double-Stranded DNA Molecules on a Gold Surface Measured Using a Surface Forces Apparatus

Di Kang, Jing Yu, Fan Xia, Jun Huang, Hongbo Zeng, Matthew Tirrell, Jacob Israelachvili, Kevin W. Plaxco

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Using a surface forces apparatus (SFA), we have studied the nanomechanical behavior of short single-stranded and partially and fully double-stranded DNA molecules attached via one end to a self-assembled monolayer on a gold surface. Our results confirm the previously proposed "mushroom-like"polymer structure for surface-attached, single-stranded DNA at low packing density and a "brush-like"structure for the same construct at higher density. At low density we observe a transition to "rigid rod"behavior upon addition of DNA complementary to the surface-attached single strand as the fraction of molecules that are double-stranded increases, with a concomitant increase in the SFA-observed thickness of the monolayer and the characteristic length of the observed repulsive forces. At higher densities, in contrast, this transition is effectively eliminated, presumably because the single-stranded state is already extended in its "brush"state. Taken together, these studies offer insights into the structure and physics of surface-attached short DNAs, providing new guidance for the rational design of DNA-modified functional surfaces.

Original languageEnglish (US)
Pages (from-to)13346-13352
Number of pages7
JournalLangmuir
Volume37
Issue number45
DOIs
StatePublished - Nov 16 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society.

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