Force Spectroscopy technique at an Atomic Force Microscope.

<p>(A) Schematic representation of the erythrocytes deposited on a poly-L-lysine-coated glass slide and an AFM tip chemically functionalized with fibrinogen molecule(s). The arrows represent the approach and retract cycles during the force spectroscopy measurements. When approaching the tip to the sample, the fibrinogen molecule may contact with cell receptor(s) and the binding between them can occur. By retracting the tip away from the sample, the binding force necessary to break this bond, at the single-molecule level, can be measured. (B) Air tapping-mode AFM images of typical circular, biconcave human erythrocytes, from healthy donors, deposited on poly-L-lysine coated glass slides (height 3D image).