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Atomic force microscopy-based microrheology reveals significant differences in the viscoelastic response between malign and benign cell lines.

Rother J, Nöding H, Mey I, Janshoff A - Open Biol (2014)

Bottom Line: Mechanical phenotyping of cells by atomic force microscopy (AFM) was proposed as a novel tool in cancer cell research as cancer cells undergo massive structural changes, comprising remodelling of the cytoskeleton and changes of their adhesive properties.In this work, we focused on the mechanical properties of human breast cell lines with different metastatic potential by AFM-based microrheology experiments.Including also other cell lines from different organs shows that the loss tangent (G″/G') increases generally with the metastatic potential from MCF-10A representing benign cells to highly malignant MDA-MB-231 cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physical Chemistry, Tammannstrasse 6, 37077 Göttingen, Germany.

ABSTRACT
Mechanical phenotyping of cells by atomic force microscopy (AFM) was proposed as a novel tool in cancer cell research as cancer cells undergo massive structural changes, comprising remodelling of the cytoskeleton and changes of their adhesive properties. In this work, we focused on the mechanical properties of human breast cell lines with different metastatic potential by AFM-based microrheology experiments. Using this technique, we are not only able to quantify the mechanical properties of living cells in the context of malignancy, but we also obtain a descriptor, namely the loss tangent, which provides model-independent information about the metastatic potential of the cell line. Including also other cell lines from different organs shows that the loss tangent (G″/G') increases generally with the metastatic potential from MCF-10A representing benign cells to highly malignant MDA-MB-231 cells.

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Related in: MedlinePlus

(a) Illustration of force mapping on cells. A deflection AFM image (contact mode) of subconfluent NMuMG cells is shown. During force mapping a force–distance curve is taken at every yellow spot. (b) Schematic drawing of the experiment: the cantilever oscillates around the indentation depth δ0 with an amplitude δ at the frequency ω. (c) Time course of force during the measurement of a force–distance curve. When the cantilever gets into contact with the sample, the force increases rapidly until the present trigger point is reached. During dwell in contact, the cantilever is excited to sinusoidal oscillations with frequencies from 5 to 200 Hz. Afterwards, the cantilever is retracted and the procedure repeated at a different position. (d) Indentation oscillation δ(ω) with frequencies from 5 to 200 Hz around the indentation depth δ0 and corresponding force signal F(ω) after detrending.
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RSOB140046F1: (a) Illustration of force mapping on cells. A deflection AFM image (contact mode) of subconfluent NMuMG cells is shown. During force mapping a force–distance curve is taken at every yellow spot. (b) Schematic drawing of the experiment: the cantilever oscillates around the indentation depth δ0 with an amplitude δ at the frequency ω. (c) Time course of force during the measurement of a force–distance curve. When the cantilever gets into contact with the sample, the force increases rapidly until the present trigger point is reached. During dwell in contact, the cantilever is excited to sinusoidal oscillations with frequencies from 5 to 200 Hz. Afterwards, the cantilever is retracted and the procedure repeated at a different position. (d) Indentation oscillation δ(ω) with frequencies from 5 to 200 Hz around the indentation depth δ0 and corresponding force signal F(ω) after detrending.

Mentions: Experiments were carried out using a commercially available MFP-3D AFM (Asylum Research, Santa Barbara, CA) placed on an inverted microscope (IX51, Olympus, Tokyo, Japan). After calibration of the spring constant of the cantilever (MLCT, Veeco, C-lever, nominal spring constant k = 0.01 N m−1) using thermal noise spectra and determination of the optical lever sensitivity, cells were imaged in contact mode. Subsequently, we used the built-in force map mode of the AFM to measure force–distance curves providing information about the local mechanical response of the cells on the previously imaged area. A typical example of subconfluent NMuMG cells is shown in figure 1a. Every spot in this particular AFM image corresponds to a single force curve in the force map measurement. A schematic drawing of the experimental set-up is shown in figure 1b. Figure 1c depicts the time course of the force recorded during the measurement of a force–distance curve modulated with a sinusoidal oscillation.Figure 1.


Atomic force microscopy-based microrheology reveals significant differences in the viscoelastic response between malign and benign cell lines.

Rother J, Nöding H, Mey I, Janshoff A - Open Biol (2014)

(a) Illustration of force mapping on cells. A deflection AFM image (contact mode) of subconfluent NMuMG cells is shown. During force mapping a force–distance curve is taken at every yellow spot. (b) Schematic drawing of the experiment: the cantilever oscillates around the indentation depth δ0 with an amplitude δ at the frequency ω. (c) Time course of force during the measurement of a force–distance curve. When the cantilever gets into contact with the sample, the force increases rapidly until the present trigger point is reached. During dwell in contact, the cantilever is excited to sinusoidal oscillations with frequencies from 5 to 200 Hz. Afterwards, the cantilever is retracted and the procedure repeated at a different position. (d) Indentation oscillation δ(ω) with frequencies from 5 to 200 Hz around the indentation depth δ0 and corresponding force signal F(ω) after detrending.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4042852&req=5

RSOB140046F1: (a) Illustration of force mapping on cells. A deflection AFM image (contact mode) of subconfluent NMuMG cells is shown. During force mapping a force–distance curve is taken at every yellow spot. (b) Schematic drawing of the experiment: the cantilever oscillates around the indentation depth δ0 with an amplitude δ at the frequency ω. (c) Time course of force during the measurement of a force–distance curve. When the cantilever gets into contact with the sample, the force increases rapidly until the present trigger point is reached. During dwell in contact, the cantilever is excited to sinusoidal oscillations with frequencies from 5 to 200 Hz. Afterwards, the cantilever is retracted and the procedure repeated at a different position. (d) Indentation oscillation δ(ω) with frequencies from 5 to 200 Hz around the indentation depth δ0 and corresponding force signal F(ω) after detrending.
Mentions: Experiments were carried out using a commercially available MFP-3D AFM (Asylum Research, Santa Barbara, CA) placed on an inverted microscope (IX51, Olympus, Tokyo, Japan). After calibration of the spring constant of the cantilever (MLCT, Veeco, C-lever, nominal spring constant k = 0.01 N m−1) using thermal noise spectra and determination of the optical lever sensitivity, cells were imaged in contact mode. Subsequently, we used the built-in force map mode of the AFM to measure force–distance curves providing information about the local mechanical response of the cells on the previously imaged area. A typical example of subconfluent NMuMG cells is shown in figure 1a. Every spot in this particular AFM image corresponds to a single force curve in the force map measurement. A schematic drawing of the experimental set-up is shown in figure 1b. Figure 1c depicts the time course of the force recorded during the measurement of a force–distance curve modulated with a sinusoidal oscillation.Figure 1.

Bottom Line: Mechanical phenotyping of cells by atomic force microscopy (AFM) was proposed as a novel tool in cancer cell research as cancer cells undergo massive structural changes, comprising remodelling of the cytoskeleton and changes of their adhesive properties.In this work, we focused on the mechanical properties of human breast cell lines with different metastatic potential by AFM-based microrheology experiments.Including also other cell lines from different organs shows that the loss tangent (G″/G') increases generally with the metastatic potential from MCF-10A representing benign cells to highly malignant MDA-MB-231 cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physical Chemistry, Tammannstrasse 6, 37077 Göttingen, Germany.

ABSTRACT
Mechanical phenotyping of cells by atomic force microscopy (AFM) was proposed as a novel tool in cancer cell research as cancer cells undergo massive structural changes, comprising remodelling of the cytoskeleton and changes of their adhesive properties. In this work, we focused on the mechanical properties of human breast cell lines with different metastatic potential by AFM-based microrheology experiments. Using this technique, we are not only able to quantify the mechanical properties of living cells in the context of malignancy, but we also obtain a descriptor, namely the loss tangent, which provides model-independent information about the metastatic potential of the cell line. Including also other cell lines from different organs shows that the loss tangent (G″/G') increases generally with the metastatic potential from MCF-10A representing benign cells to highly malignant MDA-MB-231 cells.

Show MeSH
Related in: MedlinePlus