Mechanics of Cell Morphology Linked to Substrate Rigidity

 

Yong Ni*, Martin Y.M. Chiang, Lori Henderson

 

Polymers Division, MSEL

Bldg 224, Rm 217, MS 8544

301-975-2820

301-975-4924(fax)

yong.ni@nist.gov

Mentors: Martin Y.M.Chiang

Category: Biology

*Not a Sigma Xi member

 

      When a cell binds to a substrate and forms adhesions, mechanical forces are developed in the cytoskeleton and transmitted to the deformable substrate.  These forces usually exert strong influences on cellular activities, such as migration, geometric arrangement and other morphological changes.  Recent experiments have shown that the cell adhering to a flat substrate is able to sense the substrate rigidity to modulate its behavior, since the changes of substrate stiffness alter the cellular force balance.  For example, some cells on stiffer substrates have less rounded morphologies and are more able to extend into branches than the cells on softer substrates. Also, cells prefer to migrate towards stiffer regions of a substrate with stiffness gradient. The objective of this study is to provide a theoretical basis for understanding the effects of substrate mechanics on cell behavior. The morphology of cell is characterized by the balance of strain energies (in the cell and substrate) and interfacial energy (around the adhesion edge), which depend on the cell shape. In this study, the phase field method has been adapted to model the morphology of cell adhering to a pre-stressed substrate or a substrate with stiffness gradient. Our preliminary results are in good agreement with experimental observations.