Magnetic force spectroscopy is a rapidly developing single molecule technique that has found numerous applications at the interface of physics and biology. Since the invention of the first magnetic tweezers, a number of modifications to the approach have helped to relieve the limitations of the original design while amplifying its strengths. Inventive molecular biology solutions further advance...

In interphase plant cells, the actin cytoskeleton is essential for intracellular transport and organization. To fully understand how the actin cytoskeleton functions as the structural basis for cytoplasmic organization, both molecular and physical aspects of the actin organization have to be considered. In the present review, we discuss literature that gives an insight into how cytoplasmic orga...

Numerous microtubule-associated molecular motors, including several kinesins and cytoplasmic dynein, produce opposing forces that regulate spindle and chromosome positioning during mitosis. The motility and force generation of these motors are therefore critical to normal cell division, and dysfunction of these processes may contribute to human disease. Optical tweezers provide a powerful metho...

The bond lifetime-force behavior of the immunoglobulin G (IgG)-protein A interaction has been studied with magnetic tweezers to characterize the physical properties of the bond under nonequilibrium conditions. Super-paramagnetic microparticles were developed that have a high and uniform magnetization to simultaneously apply a piconewton-scale tensile force to many thousands of IgG-protein A bon...

The optical torque wrench is a laser trapping technique that expands the capability of standard optical tweezers to torque manipulation and measurement, using the laser linear polarization to orient tailored microscopic birefringent particles. The ability to measure torque of the order of kBT (∼4 pN nm) is especially important in the study of biophysical systems at the molecular and cellular le...

A series of polycyclic frameworks with fluorinated syn-facial quinoxaline sidewalls has been prepared as potential molecular tweezers for electron-rich guest compounds. Our synthetic route to the cyclooctadiene-derived scaffolds 16a-d takes advantage of the facile isolation of a novel spirocyclic precursor 9b with the crucial syn-orientation of its two alkene moieties. The crystal structure of ...

Optoelectronic tweezers is a new technique to trap and manipulate particles with sizes ranging from tens of nanometers to hundreds of micrometers. Using optically-controlled dielectrophoretic force on a photoconductive electrode, optoelectronic tweezers enables complex, dynamic manipulation functions using light intensities up to 100,000 times lower than that of conventional laser tweezers. © 2...

We examine the large deformation elastic response of the spectrin network in a human red blood cell (RBC) on the basis of molecular-level constitutive laws. These formulations are shown to be consistent with the predictions of continuum level models for the hyperelastic deformation of RBC, and are compared with recent experimental studies of whole-cell deformation using optical tweezers stretch...

Cantilevers and optical tweezers are widely used for micromanipulating cells or biomolecules for measuring their mechanical properties. However, they do not allow easy rotary motion and can sometimes damage the handled material. We present here a system of magnetic tweezers that overcomes those drawbacks while retaining most of the previous dynamometers properties. Electromagnets are coupled to...

Optical tweezers have emerged as a powerful tool for micro and nanomanipulation. Using optical tweezers to perform automated assembly requires on-line monitoring of components in the assembly workspace. This paper presents algorithms for estimating positions and orientations of microscale and nanoscale components in the 3-Dimensional assembly workspace. Algorithms presented in this paper use im...