SIMULTANEOUS IMAGING OF THE SURFACE AND THE SUBMEMBRANEOUS CYTOSKELETON IN LIVING CELLS BY TAPPING MODE ATOMIC-FORCE MICROSCOPY

Contact and tapping mode atomic force microscopy have been wed to visu alize the surface of cultured CV-I kidney cells in aqueous medium. The height images obtained from living cells were comparable when using c ontact and tapping modes. In contrast, the corresponding, and simultan eously acquired, deflection images differed markedly Whereas, as expec ted, deflection images enhanced the surface features in the contact mo de, they revealed the presence of a filamentous network when using the tapping mode. This network became disorganized upon addition of cytoc halasin, which strongly suggests that it corresponded to the submembra neous cytoskeleton. Examination of fixed cells further supported this assumption. These data show that, in addition to the structural inform ation on the cell surface, the use of the tapping mode in liquid can a lso provide a good visualization of the membrane cytoskeleton. Tapping mode atomic force microscopy appears to be a promising technique for studying interactions between cell surface and subsurface structures, a critical step in many biological processes.