منابع مشابه
Passive all-optical force clamp for high-resolution laser trapping.
Optical traps are useful for studying the effects of forces on single molecules. Feedback-based force clamps are often used to maintain a constant load, but the response time of the feedback limits bandwidth and can introduce instability. We developed a novel force clamp that operates without feedback, taking advantage of the anharmonic region of the trapping potential where the differential st...
متن کاملMeasurement of the DNA Spring Constant Using Optical Tweezers
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, w...
متن کاملDual-trap optical tweezers with real-time force clamp control.
Single molecule force clamp experiments are widely used to investigate how enzymes, molecular motors, and other molecular mechanisms work. We developed a dual-trap optical tweezers instrument with real-time (200 kHz update rate) force clamp control that can exert 0-100 pN forces on trapped beads. A model for force clamp experiments in the dumbbell-geometry is presented. We observe good agreemen...
متن کاملTouching the microworld with force-feedback optical tweezers.
Optical tweezers are a powerful tool for micromanipulation and measurement of picoNewton sized forces. However, conventional interfaces present difficulties as the user cannot feel the forces involved. We present an interface to optical tweezers, based around a low-cost commercial force feedback device. The different dynamics of the micro-world make intuitive force feedback a challenge. We prop...
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...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2004
ISSN: 0006-3495
DOI: 10.1529/biophysj.103.037697