Tethered particle motion with single DNA molecules Single molecule λ -DNA stretching studied by microfluidics and single particle tracking Electrophoretic stretching of DNA molecules using microscale T junctions Mechanical characteristic of ssDNA∕dsDNA mo

Abstract

A simple method for tethering microbeads using single molecules of DNA is explained. We describe how to use video microscopy and particle tracking to measure the trajectories of the microbeads' motion. The trajectories are analyzed and compared to different models of tethered particle motion. In addition, the data are used to measure the elasticity of the DNA (its spring constant), and the DNA persistence length