Use of optical tweezers for colloid science

Resnick, Andrew

doi:10.1016/s0021-9797(03)00193-0

Cited by 23 publications

(18 citation statements)

References 20 publications

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“…Based on the trap characterization data and the size of the trapped particle, 37 the applied force was not more than 200 pN. The interpretation is that a localized force applied directly to the primary cilium elicited release of intracellular Ca ++ , in agreement with previous reports.…”

Section: Pushing a Trapped Microsphere Against The Cilium Correlates supporting

confidence: 87%

“…Rather, the relevant information is simply that the force applied to a cilium is within a physiologically relevant range. Two methods were used to assess the maximum applied force: holding a sphere and moving the stage, 37 and holding a sphere in an applied flow via a flow chamber. 36 Polystyrene microspheres suspended in phosphate-buffered saline ͑PBS͒ were used.…”

Section: Tweezer Characterizationmentioning

confidence: 99%

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Use of optical tweezers to probe epithelial mechanosensation

Resnick

2010

J. Biomed. Opt

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Abstract. Cellular mechanosensation mechanisms have been implicated in a variety of disease states. Specifically in renal tubules, the primary cilium and associated mechanosensitive ion channels are hypothesized to play a role in water and salt homeostasis, with relevant disease states including polycystic kidney disease and hypertension. Previous experiments investigating ciliary-mediated cellular mechanosensation have used either fluid flow chambers or micropipetting to elicit a biological response. The interpretation of these experiments in terms of the "ciliary hypothesis" has been difficult due the spatially distributed nature of the mechanical disturbance-several competing hypotheses regarding possible roles of primary cilium, glycocalyx, microvilli, cell junctions, and actin cytoskeleton exist. I report initial data using optical tweezers to manipulate individual primary cilia in an attempt to elicit a mechanotransduction response-specifically, the release of intracellular calcium. The advantage of using laser tweezers over previous work is that the applied disturbance is highly localized. I find that stimulation of a primary cilium elicits a response, while stimulation of the apical surface membrane does not. These results lend support to the hypothesis that the primary cilium mediates transduction of mechanical strain into a biochemical response in renal epithelia.

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Section: Pushing a Trapped Microsphere Against The Cilium Correlates supporting

confidence: 87%

Section: Tweezer Characterizationmentioning

confidence: 99%

Use of optical tweezers to probe epithelial mechanosensation

Resnick

2010

J. Biomed. Opt

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“…-026114 https://dx.doi.org/10.1063 tweezers͒ are particularly useful because they allow to manipulate micrometer-and sub-micrometer sized particles in a non-destructive way. [4][5][6][7] This makes optical tweezers a flexible tool which has been successfully applied in many experiments. The principle of optical trapping is based on the transfer of momentum from photons ͑typically emitted from a laser source͒ which are reflected and refracted by a trapped particle to the particle itself.…”

Section: Introductionmentioning

confidence: 99%

“…3 In this context optical trapping techniques ͑optical tweezers͒ are particularly useful because they allow to manipulate micrometer-and sub-micrometer sized particles in a non-destructive way. [4][5][6][7] This makes optical tweezers a flexible tool which has been successfully applied in many experiments.…”

Section: Introductionmentioning

confidence: 99%

Colloids as model systems for problems in statistical physics

Babič

Schmitt

Bechinger

2005

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Owing to their mesoscopic length scales, colloidal suspensions provide ideal model systems suitable for addressing many problems in the field of statistical physics. Exemplarily, we highlight the versatile nature of such systems by discussing experiments with stochastic resonance and a practical realization of a recently proposed ratchet cellular automaton. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.1839311͔Colloidal systems, i.e., micron-sized particles which are suspended in liquids, share many properties with atomic systems. Therefore, they are often referred to as model systems to address novel concepts in the context of statistical physics in a convenient way. Owing to the Brownian motion of such particles, their trajectories can be experimentally studied and allow direct comparison with numerical and theoretical investigations. Here we report on two examples to highlight the use of colloidal particles. The first example is devoted to stochastic resonance, i.e., amplification of small periodic signals in a double-well potential in the presence of noise. The second example addresses a new type of a ratchet cellular automaton which has been recently suggested as a basic element in novel computing schemes. INTRODUCTIONMolecules and atoms are always in thermal motion thereby continuously swarming and colliding with each other. While it is difficult to directly observe this motion in experiments, it can be visualized with micron-sized particles suspended in a liquid. Due to its bombardment by molecules of the liquid, a mesoscopic particle undergoes a Brownian motion which can be directly observed with a conventional microscope. When the Scottish botanist Robert Brown ͑1773-1858͒ performed his famous experiments, he used pollen from Clarkia Pulchella whose cytoplasm contained particles of about 5 m in size. 1 Such particles, which are large compared to the molecules of the solvent so that the latter can be regarded as a homogeneous background but are small enough to exhibit Brownian motion, are known as colloids.At the beginning of the 20th century, Jean Perrin performed a simple yet brilliant experiment demonstrating that the Brownian motion of a colloidal particle is just the largescale manifestation of the thermal agitation of the molecules in the liquid. This means that the energy equipartition theorem, i.e., the fact that the total mean translational kinetic energy of a molecule equals 3 / 2 k B T holds for the molecules of the liquid as well as for the colloids. In 1926, Perrin was awarded the Nobel Prize for this observation which is the cornerstone for the concept of using colloidal particles as model systems for problems in statistical physics.With sizes comparable to the wavelength of visible light, colloidal systems can be conveniently investigated with optical methods. This allows to obtain direct positional information of individual particles. Apart from the length scale which distinguishes colloids from atoms by several orders of magnitude this also applies for the characteristic time sca...

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“…As constructed, 61,62 optical tweezers create a single-beam three-dimensional (3-D) potential well due to a spatial gradient of the electric field, created by focusing a laser beam with a high-numerical-aperture microscope objective. Objects possessing a refractive index greater than the surrounding fluid medium experience a spring-like restoring force as they move away from the trap center.…”

Section: Principles Of Optical Tweezer Operationmentioning

confidence: 99%

Near real-time measurement of forces applied by an optical trap to a rigid cylindrical object

2014

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Abstract. An automated data acquisition and processing system is established to measure the force applied by an optical trap to an object of unknown composition in real time. Optical traps have been in use for the past 40 years to manipulate microscopic particles, but the magnitude of applied force is often unknown and requires extensive instrument characterization. Measuring or calculating the force applied by an optical trap to nonspherical particles presents additional difficulties which are also overcome with our system. Extensive experiments and measurements using well-characterized objects were performed to verify the system performance. © The Authors.Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Use of optical tweezers for colloid science

Cited by 23 publications

References 20 publications

Use of optical tweezers to probe epithelial mechanosensation

Use of optical tweezers to probe epithelial mechanosensation

Colloids as model systems for problems in statistical physics

Near real-time measurement of forces applied by an optical trap to a rigid cylindrical object

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