Calibration of a microcantilever.

(A). Video micrograph of the calibration of a microcantilever. The biotinylated RBC adheres to the streptavidin-coated bead and serves as a piston to transmit the force of the pipette suction pressure to the fiber. The fiber deflection is measured as a function of the suction pressure, and the force is calculated from the pressure as described in the text. (B) An example of the force-deflection relationship for a microcantilever. The force constant for this cantilever was 5.6 pN/μm.