Cell & Nucleus Deformation

Cell deformation & nucleus mechanotransduction

The optical tweezers platform SENSOCELL brings you the possibility to study cell membrane and cell nucleus mechanotransduction patways by stretching cells as a whole or manipulating cell nuclei and directly measure the applied forces:

Stretch cells as a whole by applying forces on their membrane via multiple optical traps.
Stretch and/or squeeze cell nuclei to study nuclear mechanotransduction pathways.
Stretching forces can be applied via trapped exogenous spherical particles or directly trapping endogenous trappable cellular structures like membranes or nuclei.

Would you like to try SENSOCELL with your biological system samples? Let’s do it, contact us!

Cell nucleus deformation.

Check out this research work carried out by the labs of Dr. Verena Ruprecht (Centre of Genomic Regulation, CRG), Dr. Stefan Wieser and Dr. Michael Krieg (Institute of Photonic Sciences, ICFO) where SENSOCELL was used to probe intracellular nucleus mechanics in cell extracts from zebrafish embryos:

Courtesy of Dr. Michael Krieg.

Fig. 1 Injected microspheres are used to indent the cell nucleus in both suspended and confined cells from Zebrafish embryos. Source: extracted from [1].

Cell nucleus indentation with SENSOCELL optical tweezers

Fig. 2 Cell nucleus indentation experiment performed with SENSOCELL optical tweezers system. The trapped microsphere is pushed against the nucleus (in blue) and moved away after some seconds. The cell (in green) exhibits a bleb at lower side during the measurement.

Fig. 3 Example of a nuclear force profile normalized to nuclear indentation. After the microsphere gets in contact with the nucleus, the force exhibits a characteristic time relaxation. At t=13s, the particle is moved away.

[1] V. Venturi, F. Pezzano, F. Català-Castro, H.- M. Häkkinen, S. Jiménez-Delgado, M. Colomer-Rosell, M. Marro-Sánchez, Q. Tolosa-Ramon, S. Paz-López, M. A. Valverde, P. Loza-Alvarez, M. Krieg, S. Wieser and V. Ruprecht, “The nucleus measures shape deformation for cellular proprioception and regulates adaptive morphodynamics,” Science 16 Oct 2020, Vol. 370, Issue 6514, eaba2644. DOI: 10.1126/science.aba2644.

“The nucleus measures shape deformation for cellular proprioception and regulates adaptive morphodynamics.”

Science 16 Oct 2020, Vol. 370, Issue 6514, eaba2644
DOI: 10.1126/science.aba2644

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Similar data has been obtained in preliminary tests using HELA cancer cells and RPE-1 human retina cells (samples were kindly provided by Dr. Aastha Mathur from M. Piel’s lab at Institut Curie). In this case, 3μm beads were internalized in the cells by phagocytosis:

Fig. 4 HELA cancer cells (left) and RPE-1 cells (right) with internalized microspheres that were optically trapped and manipulated to indent the fluorescently labelled cell nuclei.

Fig. 5 Trap position and force profile of a single nucleus indentation experiment.

Nucleus indentaton relaxation data HELA - RPE1

Fig. 6 Relaxation of the applied force normalized to nuclear indentation for tests using HELA and RPE-1 cells.

Cell stretching experiment.

Cell stretching application video

Summary:

In this example, we show a stretching experiment performed on a yeast cell. The experiment is done in three steps as shown in Fig. 1. No beads were used for trapping and stretching the cell. Optical trapping forces are applied over trappable cellular structures like the cell membrane and directly measured by the force sensor.

Fig. 1 In a first step, two optical traps are located on a yeast cell sharing the same location (1); force is simultaneously tracked for trap 1 (red line) and trap 2 (yellow line). Initially, F₁=F₂=0. Secondly, stretching is applied as trap 2 is moved away (2) and, following Newton’s third law of motion, F₁=-F₂. Finally, trap 2 comes back to its initial position (3) and the system relaxes back until F₁=F₂=0.

The following figure plots the obtained applied force vs. stretch ratio data, showing a s-shaped curve behavior typical of viscoelastic materials.

Fig. 2 Applied force vs stretch ratio for a yeast cell stretching experiment.

Other interesting publications related with this application:

V. Venturi, F. Pezzano, F. Català-Castro, H.- M. Häkkinen, S. Jiménez-Delgado, M. Colomer-Rosell, M. Marro-Sánchez, Q. Tolosa-Ramon, S. Paz-López, M. A. Valverde, P. Loza-Alvarez, M. Krieg, S. Wieser and V. Ruprecht, “The nucleus measures shape deformation for cellular proprioception and regulates adaptive morphodynamics,” SCIENCE | 16 Oct 2020: Vol. 370, Issue 6514, eaba2644. DOI: 10.1126/science.aba2644