Direct measurement of torque in an optical trap and its application to double-strand DNA.
We present a method that offers the possibility to directly apply and measure torque on particles in an optical trap. It can be used to rotationally manipulate biopolymers attached to appropriate particles. A flat object is trapped and oriented in the focus of a linearly polarized laser light. The direction and power of the orientational trap are controlled by the polarization state of the light. As a demonstration of the capabilities of the method, we examined the torsional stiffness of dsDNA (lambda-DNA) in its linear torsional regime by directly measuring the torque generated by the molecule.
Oroszi
László
L
Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Hungary.
Galajda
Péter
P
Kirei
Huba
H
Bottka
Sándor
S
Ormos
Pál
P
D004247:DNA / Q000737:chemistry*; D055095:Optics and Photonics; D013997:Time Factors; D019415:Torque
D004247:DNA