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Published on: April 26, 2010
Cytoskeletal Contribution to Cell Stiffness Due to Osmotic Swelling; Extending the Donnan Equilibrium
Pei-Chuan Chao1, Mettupalayam Sivaselvan1, Frederick Sachs2
1Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY, United States.
Abstract:
Cell volume regulation is commonly analyzed with a model of a closed semipermeable membrane filled with impermeant mobile solutes and the Donnan Equilibrium is used to predict the hydrostatic pressure. This traditional model ignores the fact that most cells are filled with a crosslinked cytoskeleton that is elastic and can be stretched or compressed like a sponge with no obvious need to move mobile solutes. However, calculations show that under osmotic stress, the elastic energy of the cytoskeleton is far greater than the elastic energy of the membrane. Here we expand the traditional Donnan model to include the elasticity of a cytoskeleton with fixed charges and show that cell stiffening happens without a membrane.
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