| Abstract: |
| Cell proliferation, apoptosis, and myosin-dependent contraction can generate elastic stress and strain in living tissues, which may be dissipated by internal rearrangement through cell topological transition and cytoskeletal reorganization. Moreover, cells and tissues can change their sizes in response to mechanical cues. We develop a thermodynamically consistent model to describe the above properties at the continuum level. By linearizing the model, we show that the stress follows the Maxwell-type viscoelastic relaxation. The rearrangement rate, which we call tissue fluidity, sets the stress relaxation time, and the ratio between the shear modulus and the fluidity sets the tissue viscosity.
By applying the model to tumor spheroid growth, we demonstrate the role of tissue mechanical properties, internal rearranging activities, and mechanical feedback on its size and mechanics regulation, in the context of differential growth induced by a field of growth-promoting chemical factors. We constrain the model by fitting experimental data of tumor spheroid growth and compare the results with previous modeling results. |
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