Micropipette force sensors for in vivo force measurements on single cells and multicellular microorganisms

Backholm, Matilda; Bäumchen, Oliver

doi:10.1038/s41596-018-0110-x

Cited by 39 publications

(52 citation statements)

References 69 publications

(94 reference statements)

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“…We studied the adhesion of individual living Chlamydomonas cells using micropipette force spectroscopy, following the measurement protocols described in our earlier work 28,29 (see Fig. 1).…”

Section: In Vivo Micropipette Force Spectroscopymentioning

confidence: 99%

“…1A), inspired by the measurement principle of atomic force microscopy techniques. 29 We determine the deflection of the cantilever using high-resolution optical microscopy combined with an image autocorrelation analysis that features a sub-pixel resolution of the cantilever's deflection. The force sensors were calibrated using the added weight of a variable mass, such as a water droplet attached to a freely suspended micropipette in air, or a reference cantilever.…”

Section: In Vivo Micropipette Force Spectroscopymentioning

confidence: 99%

“…We dissect the fundamental intermolecular interactions underlying microalgal adhesion by tailoring the substrate properties, while the topography of the substrates remains unchanged. We perform single-cell in vivo force spectroscopy experiments 29 with the same Chlamydomonas cell on different model substrates and provide a statistical comparison of the measured adhesion forces. Thereby, we systematically probe the effect of hydrophobic interactions, van der Waals interactions, and electrostatic interactions on microalgal adhesion.…”

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confidence: 99%

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In vivoadhesion force measurements ofChlamydomonason model substrates

2019

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Section: In Vivo Micropipette Force Spectroscopymentioning

confidence: 99%

Section: In Vivo Micropipette Force Spectroscopymentioning

confidence: 99%

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confidence: 99%

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In vivoadhesion force measurements ofChlamydomonason model substrates

2019

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“…In principle, forces can be measured simultaneously through the deflection of the micropipette. However, previous works utilizing such micropipette force sensors [30][31][32][33][34][35][36] were limited to quasistatic measurements. In this case the damping of the micropipette cantilever by hydrodynamic drag forces remains negligible, and forces can be directly recovered from the cantilever deflection and its static spring constant.…”

Section: Introductionmentioning

confidence: 99%

Dynamic force measurements on swimming Chlamydomonas cells using micropipette force sensors

Böddeker

Karpitschka

Kreis

et al. 2020

J. R. Soc. Interface.

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Flagella and cilia are cellular appendages that inherit essential functions of microbial life including sensing and navigating the environment. In order to propel a swimming microorganism they displace the surrounding fluid by means of periodic motions, while precisely-timed modulations of their beating patterns enable the cell to steer towards or away from specific locations. Characterizing the dynamic forces, however, is challenging and typically relies on indirect experimental approaches. Here, we present direct in vivo measurements of the dynamic forces of motile Chlamydomonas reinhardtii cells in controlled environments. The experiments are based on partially aspirating a living microorganism at the tip of a micropipette force sensor and optically recording the micropipette's position fluctuations with high temporal and sub-pixel spatial resolution. Spectral signal analysis allows for isolating the cell-generated dynamic forces associated to the periodic motion of the flagella from background noise. We provide an analytic elasto-hydrodynamic model for the micropipette force sensor and describe how to obtain the micropipette's full frequency response function from a dynamic force calibration. Using this approach, we find dynamic forces during the free swimming activity of individual Chlamydomonas reinhardtii cells of 23 ± 5 pN resulting from the coordinated flagellar beating with a frequency of 51 ± 6 Hz. This dynamic micropipette force sensor (DMFS) technique generalises the applicability of micropipettes as force sensors from static to dynamic force measurements, yielding a force sensitivity in the piconewton range. In addition to measurements in bulk liquid environment, we study the dynamic forces of the biflagellated microswimmer in the vicinity of a solid/liquid interface. As we gradually decrease the distance of the swimming microbe to the interface, we measure a significantly enhanced force transduction at distances larger than the maximum extend of the beating flagella, highlighting the importance of hydrodynamic interactions for scenarios in which flagellated microorganisms encounter surfaces.

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“…The understanding of cell mechanics has progressed thanks to the development of micromanipulation techniques such as micropipette aspiration [1][2][3][4][5][6][7][8][9] , indentation techniques [10][11][12][13][14][15][16][17][18] , and others [19][20][21] . Microfluidics-based approaches now allow high-throughput mechanical measurements [22][23][24][25][26][27][28][29] .…”

Section: Introductionmentioning

confidence: 99%

Single-cell immuno-mechanics: rapid viscoelastic changes are a hall-mark of early leukocyte activation

Zak

Cortés

Sadoun

et al. 2019

Preprint

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143 words/150) To accomplish their critical task of removing infected cells and fighting pathogens, leukocytes activate by forming specialized interfaces with other cells. Using an innovative micropipette rheometer, we show in three different cell types that when stimulated by microbeads mimicking target cells, leukocytes become up to ten times stiffer and more viscous. These mechanical changes initiate within seconds after contact and evolve rapidly over minutes. Remarkably, leukocyte elastic and viscous properties evolve in parallel, preserving a well-defined ratio that constitutes a mechanical signature specific to each cell type. The current results indicate that simultaneously tracking both elastic and viscous properties during an active cell process provides a new way to investigate cell mechanical processes. Our findings also suggest that dynamic immuno-mechanical measurements provide an identifier of leukocyte type and an indicator of the cell's state of activation.

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Micropipette force sensors for in vivo force measurements on single cells and multicellular microorganisms

Abstract: Up to three primary research articles where the protocol has been used and/or developed: 1. "Viscoelastic properties of the nematode Caenorhabditis elegans, a self-similar, shear-thinning worm", M.

Cited by 39 publications

References 69 publications

In vivoadhesion force measurements ofChlamydomonason model substrates

In vivoadhesion force measurements ofChlamydomonason model substrates

Dynamic force measurements on swimming Chlamydomonas cells using micropipette force sensors

Single-cell immuno-mechanics: rapid viscoelastic changes are a hall-mark of early leukocyte activation

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