Two frequently used modes of cantilever sensor operation. The first
one (A) shows the static mode where surface stress results in
cantilever bending. The second mode (B) shows the operation in
dynamic mode. Here the cantilever is actuated and vibrates at its
specific resonance frequency. Upon binding of a ligand to the
surface the resonance frequency changes and the adsorbed mass
can be calculated from that shift. The two modes can also be used
simultaneously. (C) Shows an electron microscope image of an
array with eight 750 μm long cantilevers. (D) Illustrates the liquid
handling system and the beam deflection read out of a cantilever
setup. A total of 8 Vertical Cavity Surface Emitting Lasers (VCSEL)
are used to sequentially determine cantilever deflections. The laser
beam is deflected at the end of the cantilevers to a Position
Sensitive Detector (PSD). Below the cantilever array is a peltier
element which produces a heat pulse to test the mechanical
properties of the cantilevers. Syringe pump and multi valve systems
allow a constant flow of samples to the cantilever measurement
chamber