Biology Reference
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(a)
(b)
(c)
(d)
Figure 10.2.
Attaching a living cell to the AFM cantilever. (a) The functionalized
cantilever is positioned above a cell and gently pressed onto the cell. (b) During
contact, adhesive interactions are established between the cell and functionalized
cantilever. (c) Thereafter, the cell-cantilever couple is separated from the support.
During the next minutes, irm attachment between cell and cantilever is established.
(d) A green-luorescent ibroblast (vinculin-GFP) immobilized on an AFM cantilever.
The picture is an overlay of images recorded by phase contrast and epi-luorescence
microscopy. The scale bar corresponds to 100 μm.
10.3.2 Probing Adhesive Interacons of the Cell with the
Substrate
To quantify adhesive interactions of the immobilized cell with a given
substrate, the cantilever is approached to the substrate until a preset contact
Figure 10.3.
Monitoring adhesive forces of a single cell.
The vertical approach of the
cantilever-attached cell (above) and the force acting on the cantilever (below) versus
time during an F-D cycle is depicted. The cell is approached onto a substrate until
a given force set-point is reached (black). In the constant height-mode, the vertical
position of the cell is kept constant during contact (green). Because of the viscous
properties of the cell, the force acting on the cantilever decays rapidly within the irst
seconds of contact. During retraction (blue), the cantilever bends downwards because
of the adhesion established between the cell and substrate. The steps of the retraction
F-D curve relect rupture events of the adhesive interactions that have been formed
between cell and substrate. The baseline force level is reached when all connections
between cell and substrate have been ruptured.
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