Advanced optical tweezers for the study of cellular and molecular biomechanics

Brouhard, Gary J.; Schek, Henry T.; Hunt, Alan

doi:10.1109/tbme.2002.805463

Cited by 73 publications

(38 citation statements)

References 11 publications

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“…The optical tweezers instrument used in these experiments has been described in ref. 20. The device features: (i) acousto-optic deflectors (AODs) for trap-steering, (ii) backfocal-plane interferometry with quadrant photodiode detectors (QPDs), and (iii) both differential interference contrast (DIC) and fluorescence microscopy concurrent with optical trapping.…”

Section: Methodsmentioning

confidence: 99%

“…The MT movements resulting from these interactions are observed by using a silica bead attached to the MT and held in the optical trap. Bead movements are monitored by highresolution back focal plane interferometry that records the location of the bead relative to the center of the optical trap with nanometer precision (20,21). We observe unidirectional forces and movements that explain how PEFs can direct chromosome movements without producing large local distortions of the easily deformed chromosome, and why discrete force-generating interactions between chromosome arms and single MTs are not observed in vivo.…”

mentioning

confidence: 98%

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Microtubule movements on the arms of mitotic chromosomes: Polar ejection forces quantified in vitro

Brouhard

Hunt

2005

Proc. Natl. Acad. Sci. U.S.A.

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During mitosis, ''polar ejection forces'' (PEFs) are hypothesized to direct prometaphase chromosome movements by pushing chromosome arms toward the spindle equator. PEFs are postulated to be caused by (i) plus-end-directed microtubule (MT)-based motor proteins on the chromosome arms, namely chromokinesins, and (ii) the polymerization of spindle MTs into the chromosome. However, the exact role of PEFs is unclear, because little is known about their magnitude or their forms (e.g., impulsive vs. sustained, etc.). In this study, we employ optical tweezers to bring about the lateral interaction between chromosome arms and MTs in vitro to directly measure the speed and force of the PEFs developed on chromosome arms. We find that forces are unidirectional and frequently exceed 1 pN, with maximum forces of 2-3 pN and peak velocities of 63 ؎ 41 nm͞s; the movements are ATP-dependent and exhibit a characteristic noncontinuous motion that includes displacements of >50 nm, stalls, and backwards slippage of the MT even under low loads. We perform experiments using antibodies to the chromokinesins Kid and KIF4 that identify Kid as the principal forceproducing agent for PEFs. At first glance, this motor activity appears surprisingly weak and erratic, but it explains how PEFs can guide chromosome movements without severely deforming or damaging the local chromosome structure. mitosis ͉ optical tweezers ͉ chromokinesin ͉ Kid

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 98%

Microtubule movements on the arms of mitotic chromosomes: Polar ejection forces quantified in vitro

Brouhard

Hunt

2005

Proc. Natl. Acad. Sci. U.S.A.

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“…The multiple-trap function of laser tweezers has been demonstrated and reported in a number of papers [5][6][7][8][9][10][11][12][13] and was described from the technical point of view in Ref. 12.…”

Section: Introductionmentioning

confidence: 99%

“…The second method involves quickly scanning a tightly focused single laser beam through a number of trap sites. [11][12][13] Certainly all the above techniques have some merit, but most publications describe the layouts of the multiple-trap approach, and illustrate multiple trap examples, but do not address the conditions of stability or efficiency during the multiple-trap operation. In this paper we report the development and characterization of a laser scanning multipletrapping system based on the galvano-XY and piezo-Z scan laser tweezer system described in Ref.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of multiple trapping by a single-beam laser tweezer

et al. 2005

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A multiple-trap single-beam scanning laser tweezer system was developed and characterized. Different stationary and mobile multiple-trap modes were generated for polystyrene beads in a water environment. Trapping efficiency and stability were investigated for several dynamic parameters such as transition time between the sites, waiting time on a single site, number of trapping sites, and IR laser power. Optimal parameters for efficient generation of complex arrays and matrices were determined. We demonstrate an example of a single laser beam multiple-trap application by measuring the trap's stiffness in water for our laser tweezer setup.

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“…17 Here we report on the development of a compact holographic optical tweezers system designed for collaborative work outside of the laser laboratory. The system is based on a fibre laser operating at 1070 nm, making it suitable for biological applications, 18,19 and is housed within a custom microscope where only the parts relevant to the non laser specialist are accessible. We have incorporated our own SLM control software, developed using a combination of LABVIEW and OpenGL, which is capable of generating holograms at hundreds of Hz.…”

Section: Introductionmentioning

confidence: 99%

A compact holographic optical tweezers instrument

Gibson

Bowman

Linnenberger

et al. 2012

Review of Scientific Instruments

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Visual and dynamical measurement of Rayleigh-Benard convection by using fiber-based digital holographic interferometry J. Appl. Phys. 112, 113113 (2012) Guide-star-based computational adaptive optics for broadband interferometric tomography Appl. Phys. Lett. 101, 221117 (2012) Limits of elemental contrast by low energy electron point source holography J. Appl. Phys. 110, 094305 (2011) Cantilever biosensor reader using a common-path, holographic optical interferometer Appl. Phys. Lett. 97, 221110 (2010) Extended depth of focus in a particle field measurement using a single-shot digital hologram Appl. Phys. Lett. 95, 201103 (2009) Additional information on Rev. Sci. Instrum. Holographic optical tweezers have found many applications including the construction of complex micron-scale 3D structures and the control of tools and probes for position, force, and viscosity measurement. We have developed a compact, stable, holographic optical tweezers instrument which can be easily transported and is compatible with a wide range of microscopy techniques, making it a valuable tool for collaborative research. The instrument measures approximately 30×30×35 cm and is designed around a custom inverted microscope, incorporating a fibre laser operating at 1070 nm. We designed the control software to be easily accessible for the non-specialist, and have further improved its ease of use with a multi-touch iPad interface. A high-speed camera allows multiple trapped objects to be tracked simultaneously. We demonstrate that the compact instrument is stable to 0.5 nm for a 10 s measurement time by plotting the Allan variance of the measured position of a trapped 2 μm silica bead. We also present a range of objects that have been successfully manipulated.

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Advanced optical tweezers for the study of cellular and molecular biomechanics

Cited by 73 publications

References 11 publications

Microtubule movements on the arms of mitotic chromosomes: Polar ejection forces quantified in vitro

Microtubule movements on the arms of mitotic chromosomes: Polar ejection forces quantified in vitro

Dynamics of multiple trapping by a single-beam laser tweezer

A compact holographic optical tweezers instrument

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