Mechanical response of single living cells under controlled stretch and indentation using functionalized micro force sensors

There is increasing experimental evidence suggesting that extracellular and intracellular mechanical forces and deformations have a profound influence on a wide range of cell behavior such as growth, cell division and apoptosis (programmed cell death). In order to explore how cells adapt to applied controlled lateral deformations, we developed a novel functionalized micro force sensor that forms localized adhesion sites with single cells. We demonstrated that actin network plays a dominant role in providing mechanical integrity and strength to living cells. Under indentation, however, cell response is dramatically different. Its force response is linear to a deformation scale comparable to the undeformed cell size, followed by plastic yielding. Upon unloading, force response drops sharply resulting in strong hysteresis. These findings shed new light on the current understanding of cell mechano-biology, particularly in the area of angiogenesis, atherosclerosis, artificial tissue growth, and wound healing