MEMBRANE DEFORMATION OF LIVING GLIAL-CELLS USING ATOMIC-FORCE MICROSCOPY

Using atomic force microscopy (AFM) it has been possible to detect act in filaments that are beneath the cell membrane of living cells despit e the fact that the AFM tip is applied to the surface of the cell. To determine whether the AFM tip actually penetrates or deforms the cell membrane we determined whether an intracellularly trapped fluorescent indicator was lost from cells during AFM. Using epifluorescence illumi nation to monitor the presence of fluo-3 in the cell, we found that AF M did not cause dye leakage from the cell, Further, force-distance cur ves indicated that standard tips did not penetrate the membrane while sharper Supertips(TM) did, In addition, the physiology of cells was fo und to be unaffected by AFM with standard tips since volume regulatory signal transduction mechanisms were intact in such studies. Thus, tra ditional AFM tips deform the cell membrane in order to reveal the pres ence of subcellular structures.