Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP

Quantifying the adaptive mechanical behavior of living cells is essential for the understanding of their inner working and function.*

In their article “Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP” Mark Skamrahl, Huw Colin‐York, Liliana Barbieri and Marco Fritzsche use a combination of atomic force microscopy and fluorescence recovery after photobleaching is introduced which offers simultaneous quantification and direct correlation of molecule kinetics and mechanics in living cells.*

Simultaneous quantification of the relationship between molecule kinetics and cell mechanics may thus open up unprecedented insights into adaptive mechanobiological mechanisms of cells.*

For the AFM nanoindentation tests described in their publication the authors used NanoWorld Arrow-TL2 tipless cantilevers that were functionalized with a polystyrene bead with 5 µm radius.*

 Figure 1 a from “Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP” by M. Skamrahl et al.: 
 Establishment and calibration of the optomechanical AFM–FRAP platform. a) Schematic of the AFM–FRAP setup illustrating the experimental power of simultaneous quantification of molecule kinetics and cell mechanics
Figure 1 a from “Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP” by M. Skamrahl et al.:
Establishment and calibration of the optomechanical AFM–FRAP platform. a) Schematic of the AFM–FRAP setup illustrating the experimental power of simultaneous quantification of molecule kinetics and cell mechanics

*Mark Skamrahl, Huw Colin‐York, Liliana Barbieri, Marco Fritzsche
Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP
Small 2019, 1902202
DOI: https://doi.org/10.1002/smll.201902202

Please follow this external link to the full article https://onlinelibrary.wiley.com/doi/full/10.1002/smll.201902202

Open Access: The article « Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP » by Mark Skamrahl, Huw Colin‐York, Liliana Barbieri and Marco Fritzsche is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other thirdparty material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Rapid changes in tissue mechanics regulate cell behaviour in the developing embryonic brain

In their short report “Rapid changes in tissue mechanics regulate cell behaviour in the developing embryonic brain” published in January 2019, Amelia J Thompson, Eva K Pillai, Ivan B Dimov, Sarah K Foster, Christine E Holt, and Kristian Franze describe how they used time-lapse in vivo atomic force microscopy (tiv-AFM), a method that combines sensitive upright epi-fluorescence imaging of opaque samples, with iterated AFM indentation measurements of in vivo tissue at cellular resolution and at a time scale of tens of minutes, in order to enable time-resolved measurements of developmental tissue mechanics.* The technique developed by Thompson, Pillai et al. is a useful tool that can help elucidate how variations in stiffness control the brain wiring process. It could also be used to look into how other developmental or regenerative processes, such as the way neurons reconnect after injuries to thebrain or spinal cord, may be regulated by mechanical tissue properties.* NanoWorld Arrow-TL1 tipless cantilevers were used for the AFM-based stiffness measurements. (Monodisperse spherical polystyrene beads were glued to the cantilever ends as probes.)
NanoWorld Arrow-TL1 tipless cantilever for atomic force microscopy
NanoWorld Arrow-TL1 tipless AFM cantilever
*Amelia J Thompson, Eva K Pillai, Ivan B Dimov, Sarah K Foster, Christine E Holt, Kristian Franze Rapid changes in tissue mechanics regulate cell behaviour in the developing embryonic brain eLife 2019; 8:e39356 DOI: https://doi.org/10.7554/eLife.39356 Please follow this external link to the full article: https://cdn.elifesciences.org/articles/39356/elife-39356-v1.pdf Open Access: The article « Rapid changes in tissue mechanics regulate cell behaviour in the developing embryonic brain » by Amelia J Thompson et al. is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.  

Adhesion strategies of Dictyostelium discoideum – a force spectroscopy study

“Motile cells require reversible adhesion to solid surfaces to accomplish force transmission upon locomotion. In contrast to mammalian cells, Dictyostelium discoideum ( a soil dwelling amoeba) cells do not express integrins forming focal adhesions but are believed to rely on more generic interaction forces that guarantee a larger flexibility; even the ability to swim has been described for Dictyostelium discoideum (D.d.).”*

In order to understand the origin of D.d. adhesion, Nadine Kamprad, Hannes Witt, Marcel Schröder, Christian Titus Kreis, Oliver Bäumchen, Andreas Janshoff and Marco Tarantola  describe in their publication “Adhesion strategies of Dictyostelium discoideum – a force spectroscopy study”* how they realized and modified a variety of conditions for the amoeba comprising the absence and presence of the specific adhesion protein Substrate Adhesion A (sadA), glycolytic degradation, ionic strength, surface hydrophobicity and strength of van der Waals interactions by generating tailored model substrates. By employing AFM-based single cell force spectroscopy (using NanoWorld Arrow-TL2 tipless cantilevers) they could show that experimental force curves upon retraction exhibit two regimes described in detail in the article cited above. The study describes a versatile mechanism that allows the cells to adhere to a large variety of natural surfaces under various conditions.

Fig. 2 A from "Adhesion strategies of Dictyostelium discoideum – a force spectroscopy study": Cell parametrization: β, angle between the normal on the cell membrane and the cell axis; R1, contact radius between the cell and substrate; R0, equatorial cell radius; R2, contact radius between the cell and cantilever, ϕ1 contact angle towards the substrate; ϕ2, contact angle between the cell and cantilever, in the background is a section of the confocal image in B. B: morphology of the carA-1-GFP labelled D.d. cell attached to the cantilever subjected to a pulling force of 0.2 nN. NanoWorld Arrow-TL2 tipless cantilevers were used.
Fig. 2 A from “Adhesion strategies of Dictyostelium discoideum – a force spectroscopy study” by N. Kamprad et al.: Cell parametrization: β, angle between the normal on the cell membrane and the cell axis; R1, contact radius between the cell and substrate; R0, equatorial cell radius; R2, contact radius between the cell and cantilever, ϕ1 contact angle towards the substrate; ϕ2, contact angle between the cell and cantilever, in the background is a section of the confocal image in B. B: morphology of the carA-1-GFP labelled D.d. cell attached to the cantilever subjected to a pulling force of 0.2 nN.

*Nadine Kamprad, Hannes Witt, Marcel Schröder, Christian Titus Kreis, Oliver Bäumchen, Andreas Janshoff, Marco Tarantola
Adhesion strategies of Dictyostelium discoideum – a force spectroscopy study
Nanoscale, 2018, 10, 22504-22519
DOI: 10.1039/C8NR07107A

To read the full article follow this external link: https://pubs.rsc.org/en/content/articlehtml/2018/nr/c8nr07107a

Open Access The article “Adhesion strategies of Dictyostelium discoideum – a force spectroscopy study” by Nadine Kamprad, Hannes Witt, Marcel Schröder, Christian Titus Kreis, Oliver Bäumchen, Andreas Janshoff and Marco Tarantola is licensed under a Creative Commons Attribution 3.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/.