Measurement of the DNA Spring Constant Using Optical Tweezers
نویسندگان
چکیده
An optical trap was used to measure the relationship between restoring force and displacement of a 1.26 μm polystyrene microsphere attached to a 3.5 kilobase-pair DNA strand. Fitting to a wormlike chain model, the persistence length of the DNA molecule was measured as 53.0± 11.6 nm, and the contour length was measured as 713 ± 36 nm. The Hookean spring constant of DNA, at small displacements, was found to be 0.162 ± 0.035 pN/μm. These are in satisfactory agreement with accepted results.
منابع مشابه
Simultaneous calibration of optical tweezers spring constant and position detector response.
We demonstrate a fast and direct calibration method for systems using a single laser for optical tweezers and particle position detection. The method takes direct advantage of back-focal-plane interferometry measuring not an absolute but a differential position, i.e. the position of the trapped particle relative to the center of the optical tweezers. Therefore, a fast step-wise motion of the op...
متن کاملmeasuring viscoelastic properties of Red Blood Cell using optical tweezers
Efforts have been made to study the behavior of complex materials in micrometer dimensions with various techniques. One of these methods is the use of optical tweezers for biophysical applications. Red blood cells, as the most abundant blood-forming cells, play an important role in the life of living organisms, and their unique mechanical properties are important. In this report, the study of s...
متن کاملMultiplying optical tweezers force using a micro-lever.
This study presents a photo-driven micro-lever fabricated to multiply optical forces using the two-photon polymerization 3D-microfabrication technique. The micro-lever is a second class lever comprising an optical trapping sphere, a beam, and a pivot. A micro-spring is placed between the short and long arms to characterize the induced force. This design enables precise manipulation of the micro...
متن کاملThe effect of integration time on fluctuation measurements: calibrating an optical trap in the presence of motion blur.
Dynamical instrument limitations, such as finite detection bandwidth, do not simply add statistical errors to fluctuation measurements, but can create significant systematic biases that affect the measurement of steady-state properties. Such effects must be considered when calibrating ultra-sensitive force probes by analyzing the observed Brownian fluctuations. In this article, we present a nov...
متن کاملVisco-elastic membrane tethers extracted from Escherichia coli by optical tweezers.
Tethers were created between a living Escherichia coli bacterium and a bead by unspecifically attaching the bead to the outer membrane and pulling it away using optical tweezers. Upon release, the bead returned to the bacterium, thus showing the existence of an elastic tether between the bead and the bacterium. These tethers can be tens of microns long, several times the bacterial length. Using...
متن کامل