Calibration of Optical Tweezers for In Vivo Force Measurements: How do Different Approaches Compare?

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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Optical manipulation of single molecules in the living cell

Physical Chemistry Chemical Physics ◽

10.1039/c4cp00208c ◽

2014 ◽

Vol 16 (25) ◽

pp. 12614-12624 ◽

Cited By ~ 27

Author(s):

Kamilla Norregaard ◽

Liselotte Jauffred ◽

Kirstine Berg-Sørensen ◽

Lene B. Oddershede

Keyword(s):

Optical Tweezers ◽

Living Cell ◽

Single Molecules ◽

Optical Manipulation ◽

Force Measurements

Optical tweezers are the only nano-tools capable of manipulating and performing force-measurements on individual molecules and organelles inside the living cell. We present methodologies for in vivo calibration and exciting recent results.

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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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Force generation by protein–DNA co-condensation

Nature Physics ◽

10.1038/s41567-021-01285-1 ◽

2021 ◽

Cited By ~ 1

Author(s):

Thomas Quail ◽

Stefan Golfier ◽

Maria Elsner ◽

Keisuke Ishihara ◽

Vasanthanarayan Murugesan ◽

...

Keyword(s):

Optical Tweezers ◽

Self Assembly ◽

Spider Silk ◽

Regulatory Elements ◽

Heterochromatin Formation ◽

First Order Phase Transition ◽

Dna Strand ◽

First Order Phase

AbstractInteractions between liquids and surfaces generate forces1,2 that are crucial for many processes in biology, physics and engineering, including the motion of insects on the surface of water3, modulation of the material properties of spider silk4 and self-assembly of microstructures5. Recent studies have shown that cells assemble biomolecular condensates via phase separation6. In the nucleus, these condensates are thought to drive transcription7, heterochromatin formation8, nucleolus assembly9 and DNA repair10. Here we show that the interaction between liquid-like condensates and DNA generates forces that might play a role in bringing distant regulatory elements of DNA together, a key step in transcriptional regulation. We combine quantitative microscopy, in vitro reconstitution, optical tweezers and theory to show that the transcription factor FoxA1 mediates the condensation of a protein–DNA phase via a mesoscopic first-order phase transition. After nucleation, co-condensation forces drive growth of this phase by pulling non-condensed DNA. Altering the tension on the DNA strand enlarges or dissolves the condensates, revealing their mechanosensitive nature. These findings show that DNA condensation mediated by transcription factors could bring distant regions of DNA into close proximity, suggesting that this physical mechanism is a possible general regulatory principle for chromatin organization that may be relevant in vivo.

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Accuracy of Orthodontic Force and Tooth Movement Measurements

British Journal of Orthodontics ◽

10.1179/bjo.23.3.241 ◽

1996 ◽

Vol 23 (3) ◽

pp. 241-248 ◽

Cited By ~ 8

Author(s):

Dan Lundgren ◽

Py Owman-Moll ◽

Jüri Kurol ◽

Birgit Mårtensson

Keyword(s):

Tooth Movement ◽

Mean Value ◽

Measurement Methods ◽

Calibration Data ◽

Force Measurements ◽

Accuracy Of Measurement ◽

Measuring Machine ◽

Initial Force ◽

Level Of Agreement

This study was designed to test the accuracy of measurement methods for assessment of force and tooth movement in orthodontic procedures. Daily in vivo measurements of the force produced by activated archwires showed that the initial force declined substantially (by 20 per cent of mean value) within 3 days. Both the ‘trueness’ (validity) and precision of the force measurements, obtained with a strain gauge, were found to be high (SD values were 1·0 cN and 0·4 cN, respectively). Horizontal tooth movements were measured with three different instruments: a slide calliper, a co-ordinate measuring machine, and laser measuring equipment based on holograms. There was a good level of agreement between these methods. This was also confirmed by calibration data. The precision of the methods was (SD values) 0·06, 0·07, and 0·13 mm, respectively. The benefits of the use of the co-ordinate measuring machine are obvious, since it can measure tooth movements in relation to reference planes in all directions.

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3-D in vivo force measurements on mandibular implants supporting overdentures. A comparative study.

Clinical Oral Implants Research ◽

10.1034/j.1600-0501.1996.070413.x ◽

1996 ◽

Vol 7 (4) ◽

pp. 387-396 ◽

Cited By ~ 69

Author(s):

R. Mericske-stern ◽

M. Piotti ◽

G. Sirtes

Keyword(s):

Comparative Study ◽

Force Measurements

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Rational design of protein-specific folding modifiers

10.1101/2020.04.28.064113 ◽

2020 ◽

Author(s):

Anirban Das ◽

Anju Yadav ◽

Mona Gupta ◽

R Purushotham ◽

Vishram L. Terse ◽

...

Keyword(s):

Single Molecule ◽

Rational Design ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Force Measurements ◽

Folding Nucleus ◽

Dynamics Simulations ◽

General Method

AbstractProtein folding can go wrong in vivo and in vitro, with significant consequences for the living cell and the pharmaceutical industry, respectively. Here we propose a general design principle for constructing small peptide-based protein-specific folding modifiers. We construct a ‘xenonucleus’, which is a pre-folded peptide that resembles the folding nucleus of a protein, and demonstrate its activity on the folding of ubiquitin. Using stopped-flow kinetics, NMR spectroscopy, Förster Resonance Energy transfer, single-molecule force measurements, and molecular dynamics simulations, we show that the ubiquitin xenonucleus can act as an effective decoy for the native folding nucleus. It can make the refolding faster by 33 ± 5% at 3 M GdnHCl. In principle, our approach provides a general method for constructing specific, genetically encodable, folding modifiers for any protein which has a well-defined contiguous folding nucleus.

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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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