Login / Signup

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

Di KangJing YuFan XiaJun HuangHongbo ZengMatthew V TirrellJacob N IsraelachviliKevin William Plaxco
Published in: Langmuir : the ACS journal of surfaces and colloids (2021)
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.
Keyphrases
  • nucleic acid
  • circulating tumor
  • single molecule
  • binding protein
  • cell free
  • magnetic resonance
  • magnetic resonance imaging
  • staphylococcus aureus
  • high resolution
  • circulating tumor cells
  • solid state
  • case control