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Surface morphology and mechanical properties of MDCK monolayers by atomic force microscopy
1Department of Physics, University of California Santa Barbara 93106.
Journal of Cell Science
|May 1, 1994
Summary
Atomic force microscopy (AFM) reveals the mechanical properties of MDCK cell surfaces. Cell membrane deformation significantly contributes to image contrast, with glutaraldehyde rapidly stiffening the membrane.
Area of Science:
- Cell biology
- Biophysics
- Surface science
Background:
- Madin-Darby Canine Kidney (MDCK) cell monolayers are a model for epithelial tissue.
- Atomic force microscopy (AFM) offers high-resolution imaging of biological surfaces.
Purpose of the Study:
- To characterize the morphology and mechanical stability of the apical surface of MDCK cell monolayers using AFM.
- To compare these properties with a transformed MDCK cell line (R5) expressing the K-ras oncogene.
Main Methods:
- AFM imaging of living MDCK cells in physiological solution.
- AFM force measurements to determine mechanical properties (spring constant).
- Real-time monitoring of mechanical changes during glutaraldehyde fixation.
Main Results:
- AFM visualized cell boundaries, nuclei in thin areas, and two types of surface protrusions.
- Transformed R5 cells showed different morphology and allowed visualization of intracellular structures not seen by SEM.
- MDCK apical plasma membrane is soft (0.002 N/m spring constant); glutaraldehyde rapidly stiffened it.
Conclusions:
- Plasma membrane deformation is a key factor in AFM contrast for these cells.
- AFM provides insights into cell surface morphology and real-time mechanical property changes.
- Differences observed between MDCK and R5 cells highlight the impact of oncogene expression on cell mechanics.