Highly sensitive force measurements in an optically generated, harmonic hydrodynamic trap

AbstractThe use of optical tweezers to measure forces acting upon microscopic particles has revolutionised fields from material science to cell biology. However, despite optical control capabilities, this technology is highly constrained by the material properties of the probe, and its use may be limited due to concerns about the effect on biological processes. Here we present a novel, optically controlled trapping method based on light-induced hydrodynamic flows. Specifically, we leverage optical control capabilities to convert a translationally invariant topological defect of a flow field into an attractor for colloids in an effectively one-dimensional harmonic, yet freely rotatable system. Circumventing the need to stabilise particle dynamics along an unstable axis, this novel trap closely resembles the isotropic dynamics of optical tweezers. Using magnetic beads, we explicitly show the existence of a linear force-extension relationship that can be used to detect femtoNewton-range forces with sensitivity close to the thermal limit. Our force measurements remove the need for laser-particle contact, while also lifting material constraints, which renders them a particularly interesting tool for the life sciences and engineering.

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Hemodynamic forces can be accurately measured in vivo with optical tweezers

10.1101/150367 ◽

2017 ◽

Author(s):

Sébastien Harlepp ◽

Fabrice Thalmann ◽

Gautier Follain ◽

Jacky G. Goetz

Keyword(s):

Optical Tweezers ◽

Cell Biology ◽

Accurate Determination ◽

Force Measurements ◽

Hemodynamic Forces ◽

Non Invasive ◽

Drag Forces ◽

Measured Flow ◽

Living Organisms

AbstractForce sensing and generation at the tissular and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows non-invasive probing of pico-Newton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles rely in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here, we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether, this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.

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Hemodynamic forces can be accurately measured in vivo with optical tweezers

Molecular Biology of the Cell ◽

10.1091/mbc.e17-06-0382 ◽

2017 ◽

Vol 28 (23) ◽

pp. 3252-3260 ◽

Cited By ~ 12

Author(s):

Sébastien Harlepp ◽

Fabrice Thalmann ◽

Gautier Follain ◽

Jacky G. Goetz

Keyword(s):

Optical Tweezers ◽

Cell Biology ◽

Accurate Determination ◽

Force Measurements ◽

Hemodynamic Forces ◽

Drag Forces ◽

Measured Flow ◽

Living Organisms

Force sensing and generation at the tissue and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows noninvasive probing of piconewton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles lie in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such a method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.

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Calibration of dynamic holographic optical tweezers for force measurements on biomaterials

Optics Express ◽

10.1364/oe.16.020987 ◽

2008 ◽

Vol 16 (25) ◽

pp. 20987 ◽

Cited By ~ 49

Author(s):

Astrid van der Horst ◽

Nancy R. Forde

Keyword(s):

Optical Tweezers ◽

Force Measurements ◽

Holographic Optical Tweezers

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Highly-sensitive magneto-optical sensors based on thin transmission-type one-dimensional magnetophotonic crystals for the visualization of magnetic fields

Chinese Journal of Physics ◽

10.1016/j.cjph.2017.05.022 ◽

2017 ◽

Vol 55 (4) ◽

pp. 1181-1188 ◽

Cited By ~ 2

Author(s):

Mehdi Zamani ◽

Majid Ghanaatshoar

Keyword(s):

Magnetic Fields ◽

Optical Sensors ◽

One Dimensional ◽

Highly Sensitive ◽

Magnetophotonic Crystals

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Cell Biology of Conidial Anastomosis Tubes in Neurospora crassa

Eukaryotic Cell ◽

10.1128/ec.4.5.911-919.2005 ◽

2005 ◽

Vol 4 (5) ◽

pp. 911-919 ◽

Cited By ~ 116

Author(s):

M. Gabriela Roca ◽

Jochen Arlt ◽

Chris E. Jeffree ◽

Nick D. Read

Keyword(s):

Neurospora Crassa ◽

Optical Tweezers ◽

Cell Biology ◽

Transmembrane Protein ◽

Mitogen Activated Protein Kinase ◽

Cellular Element ◽

Hyphal Fusion ◽

Self Recognition ◽

Mitogen Activated Protein ◽

Germ Tubes

ABSTRACT Although hyphal fusion has been well documented in mature colonies of filamentous fungi, it has been little studied during colony establishment. Here we show that specialized hyphae, called conidial anastomosis tubes (CATs), are produced by all types of conidia and by conidial germ tubes of Neurospora crassa. The CAT is shown to be a cellular element that is morphologically and physiologically distinct from a germ tube and under separate genetic control. In contrast to germ tubes, CATs are thinner, shorter, lack branches, exhibit determinate growth, and home toward each other. Evidence for an extracellular CAT inducer derived from conidia was obtained because CAT formation was reduced at low conidial concentrations. A cr-1 mutant lacking cyclic AMP (cAMP) produced CATs, indicating that the inducer is not cAMP. Evidence that the transduction of the CAT inducer signal involves a putative transmembrane protein (HAM-2) and the MAK-2 and NRC-1 proteins of a mitogen-activated protein kinase signaling pathway was obtained because ham-2, mak-2, and nrc-1 mutants lacked CATs. Optical tweezers were used in a novel experimental assay to micromanipulate whole conidia and germlings to analyze chemoattraction between CATs during homing. Strains of the same and opposite mating type were shown to home toward each other. The cr-1 mutant also underwent normal homing, indicating that cAMP is not the chemoattractant. ham-2, mak-2, and nrc-1 macroconidia did not attract CATs of the wild type. Fusion between CATs of opposite mating types was partially inhibited, providing evidence of non-self-recognition prior to fusion. Microtubules and nuclei passed through fused CATs.

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Ripping RNA by Force using Gaussian Network Models

10.1101/075820 ◽

2016 ◽

Author(s):

Changbong Hyeon ◽

D. Thirumalai

Keyword(s):

Optical Tweezers ◽

Single Molecule ◽

Cross Correlation ◽

Network Models ◽

Force Extension ◽

Correlation Matrices ◽

Rna Molecules ◽

Allosteric Communication ◽

Ion Effects ◽

Gaussian Network

AbstractUsing force as a probe to map the folding landscapes of RNA molecules has become a reality thanks to major advances in single molecule pulling experiments. Although the unfolding pathways under tension are complicated to predict studies in the context of proteins have shown that topology plays is the major determinant of the unfolding landscapes. By building on this finding we study the responses of RNA molecules to force by adapting Gaussian network model (GNM) that represents RNAs using a bead-spring network with isotropic interactions. Cross-correlation matrices of residue fluctuations, which are analytically calculated using GNM even upon application of mechanical force, show distinct allosteric communication as RNAs rupture. The model is used to calculate the force-extension curves at full thermodynamic equilibrium, and the corresponding unfolding pathways of four RNA molecules subject to a quasi-statically increased force. Our study finds that the analysis using GNM captures qualitatively the unfolding pathway of T. ribozyme elucidated by the optical tweezers measurement. However, the simple model is not sufficient to capture subtle features, such as bifurcation in the unfolding pathways or the ion effects, in the forced-unfolding of RNAs.

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Force measurement goes to femto-Newton sensitivity of single microscopic particle

Light Science & Applications ◽

10.1038/s41377-021-00684-6 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Xiaohe Zhang ◽

Bing Gu ◽

Cheng-Wei Qiu

Keyword(s):

Thermal Noise ◽

Force Measurement ◽

Force Measurements ◽

Weak Force ◽

Microscopic Particle ◽

Highly Sensitive

AbstractHighly sensitive force measurements of a single microscopic particle with femto-Newton sensitivity have remained elusive owing to the existence of fundamental thermal noise. Now, researchers have proposed an optically controlled hydrodynamic manipulation method, which can measure the weak force of a single microscopic particle with femto-Newton sensitivity.

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Bio-Molecular Applications of Recent Developments in Optical Tweezers

Biomolecules ◽

10.3390/biom9010023 ◽

2019 ◽

Vol 9 (1) ◽

pp. 23 ◽

Cited By ~ 17

Author(s):

Dhawal Choudhary ◽

Alessandro Mossa ◽

Milind Jadhav ◽

Ciro Cecconi

Keyword(s):

Photonic Crystal ◽

Optical Tweezers ◽

Single Molecule ◽

Continuous Wave ◽

Imaging Techniques ◽

Resolving Power ◽

Optical Traps ◽

Laser Source ◽

One Dimensional

In the past three decades, the ability to optically manipulate biomolecules has spurred a new era of medical and biophysical research. Optical tweezers (OT) have enabled experimenters to trap, sort, and probe cells, as well as discern the structural dynamics of proteins and nucleic acids at single molecule level. The steady improvement in OT’s resolving power has progressively pushed the envelope of their applications; there are, however, some inherent limitations that are prompting researchers to look for alternatives to the conventional techniques. To begin with, OT are restricted by their one-dimensional approach, which makes it difficult to conjure an exhaustive three-dimensional picture of biological systems. The high-intensity trapping laser can damage biological samples, a fact that restricts the feasibility of in vivo applications. Finally, direct manipulation of biological matter at nanometer scale remains a significant challenge for conventional OT. A significant amount of literature has been dedicated in the last 10 years to address the aforementioned shortcomings. Innovations in laser technology and advances in various other spheres of applied physics have been capitalized upon to evolve the next generation OT systems. In this review, we elucidate a few of these developments, with particular focus on their biological applications. The manipulation of nanoscopic objects has been achieved by means of plasmonic optical tweezers (POT), which utilize localized surface plasmons to generate optical traps with enhanced trapping potential, and photonic crystal optical tweezers (PhC OT), which attain the same goal by employing different photonic crystal geometries. Femtosecond optical tweezers (fs OT), constructed by replacing the continuous wave (cw) laser source with a femtosecond laser, promise to greatly reduce the damage to living samples. Finally, one way to transcend the one-dimensional nature of the data gained by OT is to couple them to the other large family of single molecule tools, i.e., fluorescence-based imaging techniques. We discuss the distinct advantages of the aforementioned techniques as well as the alternative experimental perspective they provide in comparison to conventional OT.

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