Download Measuring the dynamics of single tethered DNA

Measuring the dynamics of single tethered DNA
Moshe Lindner, Guy Nir, Anat Vivante & Yuval Garini
Physics Department and Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900, Israel
Tethered particle motion (TPM) is a well known method for single DNA molecule
studies. In TPM, one end of the target molecule is attached to a surface while its other
end is attached to a probe. The probe diffuses in a restricted volume due to the DNA
and its position is measured many times. From the gathered distribution one extracts
the equilibrium state characteristics of the DNA.
We developed a method for studying the dynamics of single DNAs, based on rapid
frame-rate imaging. It is achieved by using gold nano particles as probes; the intense
plasmonic scattering from these particles allows using short exposure time.
We therefore measure the dynamics of the DNA motion and not only its equilibrium
state. It is analyzed according to the spring-like behavior of a DNA molecule by using
Smoluchowski's equation that describes the time development of a diffusing particle
under harmonic potential.
This method has a great potential for measuring short time interactions and deviations
from equilibrium that cannot be measured using standard equilibrium-based methods.