Examples of results of scanning cells with an atomic force microscope in contact mode in liquid

Petri P. Lehenkari, Guillaume T. Charras, Stephen A. Nesbitt and Mike A. Horton

Figure 3. Examples of results of scanning cells with an atomic force microscope in contact mode in liquid. (a) An atomic force microscopy image of a live osteoblast (i.e. a bone cell that synthesises bone matrix), which has been scanned in contact mode using a constant force (1 nN). Prominent cytoskeletal fibres can be seen within the cell; these are evident because the downward force on the tip of the atomic force microscope allowed the relatively rigid cytoskeleton to be ‘seen’ through the compliant cell membrane. (b) An atomic force microscopy image of similar osteoblasts to that shown in part (a), but after pre-treatment with a commonly used histological aldehyde fixative. Note the change in morphology compared with that shown in (a); the underlying cytoskeletal elements are less visible in the fixed cells, because they are ‘stiffer’ (i.e. have a higher elastic modulus). Additional granular structures are evident in the fixed cells; these are fixation artifacts. These images were produced using a modified TopoMetrix Explorer^TM atomic force microscope (Ref. 9) (fig003mhu).