Recent experiments by Arnold et al. (ChemPhysChem, vol. 5, 2004, p383 ) revealed that a distance of less than 58-73 nm between receptor-ligand bonds is necessary to ensure focal adhesion in cells adhering to ligand-coated substrate. An elegant solution to this problem is supplied by Lin, Inamdar, and Freund. JMPS, 2008, 56, 242 , J. Mat. Sci. 2007, 42, 8907 .

In order to achieve a wide variety of biological phenomena, the abilities of cells to contact effectively and interact specifically with neighboring media play a central role. It is known that cells can sense the chemical and mechanical properties of surrounding systems and regulate their adhesion and movement through binding protein molecules within cell membrane. The kinetics of binding molecules interacting with ligands is of great interest in biophysical society. There are lots of discussions and contributions on cell mechanics from our mechanical society, e.g.

As stated by Richard Vinci and Oliver Kraft in the announcement of 2008 Gordon Research Conference on Thin Film and Small-Scale Mechanical Behavior, there is a compelling need to understand the critical roles of different deformation mechanisms in structures with small characteristic dimensions, like nanocrystals and thin films. We have recently studied deformation behaviors in nanostructured materials and thin films with deformation mechanisms including grain-boundary diffusion, grain-boundary sliding, and grain-interior plasticity. Some interesting mechanical phenomena associated with heterogeneous grain-boundary properties are found and summarized here.