Aug 16 2006
Ever more experiments show that a cell is very sensitive to the mechanic force and deformation, and its shape, structure and functions change accordingly. Protein molecules play an important role in the cellular adhesion and signal transfer. For example, the adhesive contact between two cells or a cell and its base is found to be formed via adhesion between a receptor and its ligand, which is a protein molecule. On the other hand, being acting by a mechanic force, a protein molecule may be deformed and in this condition, the adhesive strength between a receptor and its ligand will be reduced. In recent years, the theory of contact mechanics saw many applications and encouraging developments in explanation of adhesive mechanisms of some organism such as gecko, flies and cricket.
In cooperation with a GAO Huajian from Brown University, CHEN Shaohua from the CAS Institute of Mechanics recently revealed a possible mechanic mechanism for a cell or a bio-molecule to perceive of environmental changes. The work was published in a recent issue of Journal of the Mechanics and Physics of Solids.
The researchers established a generalized JKR model for non-slipping adhesive contact between two dissimilar elastic spheres subjected to a pair of pulling forces and a mismatch strain. They explore the full elastic solution to the problem as well as the so-called non-oscillatory solution in which tension and shear tractions along the contact interface is decoupled from each other. The model indicates that the mismatch strain has significant effect on the contact area and the pull-off process. Under a finite pulling force, a pair of adhering spheres is predicted to break apart spontaneously at a critical mismatch strain. This study suggests an adhesion mediated deformation sensing mechanism by which cells and molecules can detect mechanical signals in the environment via adhesive interactions.
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