A comparative atomic force microscopy study on living skin fibroblasts andliver endothelial cells

Atomic force microscopy (AFM) has been used to image a wide variety of cell s and has proven to be successful in cellular imaging, by comparing results obtained by AFM with SEM or TEM. The aim of the present study was to inves tigate further the conditions for AFM imaging of living cells and compare t he results with those obtained by SEM. We chose to image skin fibroblast an d liver sinusoidal endothelial cells of two different sources, because thes e cells have been well described and characterized in earlier studies. AFM imaging of living cells mainly reveals submembranous structures, which coul d not be observed by SEM. This concerns the visualization of the overall cy toskeletal architecture and organelles, without the necessity of any prepar ative steps. The AFM study of living cells allows a time lapse study of dyn amic changes of the actin cytoskeleton under the influence of the cytoskele ton-disturbing drug cytochalasin B in cells that can be followed individual ly during the process. However, softer samples, such as the fenestrated par ts of living rat liver sinusoidal endothelial cells in culture could not be visualized. Apparently, these cell parts are disrupted due to Lip-sample i nteraction in contact mode. To avoid the lateral forces and smearing artefa cts of contact mode AFM, non-contact imaging was applied, resulting in imag es of higher quality. Still, endothelial fenestrae could not be visualized. in contrast, contact imaging of immortomouse liver sinusoidal endothelial cells, which are devoid of fenestrae, could easily be performed and reveale d a detailed filamentous cytoskeleton.