Intra-Cellular Measurements of Nanodynamics and Nanomechanics by Nanoendoscopy AFM

Recently, we have developed in-cell AFM technique referred to as Nanoendoscopy AFM (NE-AFM). In this method, we insert a needle-like probe vertically into a living cell and direct interaction between the tip and intra-cellular components are detected. So far, we have successfully visualized intra-cellular structures such as nucleus, actin stress fibers, actin cortical fibers, and focal adhesion without giving significant damage to the cells. As the next step, now we are exploring the possibility of intra-cellular nanomechanical measurements. For example, we can directly indent the nuclear surface and produce nanomechanical maps of the nuclear surface. The nuclear elasticity is closely related to various diseases known and laminopathy, aging and infection. Thus, there is strong needs for direct quantitative measurements of nuclear elasticity. Meanwhile, we also investigate correlation between dynamic structural changes and nanomechanical properties. So far, we measured elasticity changes during the growth and disassembling of focal adhesions. These measurements suggest stiffening and softening of the focal adhesions during their growth and disassembling, respectively. These results demonstrate the potential of NE-AFM for opening up various possibilities of intra-cellular nanomechanics studies.