Surface functionalization of a cantilever sensor

Cantilever sensors are highly flexible and sensitive devices. By coating the cantilever surface with a material that selectively adsorbs or binds a target substance, a cantilever can be converted into a highly selective chemical and biochemical sensor. Cantilevers transform a chemical reaction into a mechanical motion, which can be measured directly by the deflection of a light source (laser) from the cantilever surface. Adsorption of different alkanethiols on the gold coated cantilever surface produce different signals due to the bending of the cantilever when exposed to an external stimuli, in the case of this study it is surface stress. The phenomena of surface stress will be investigated relative to the formation of self-assembled monolayers on the surface of the cantilever, resulting in functionalization of the gold surface. The cantilever sensor’s response to various alkanethiols in solution ranging in alkane chain length and varying in functional groups will be observed in real-time. All experiments are performed with a silicon-nitride, gold-coated cantilever that is approximately 100-200 µm in length, 20-40 µm in width, and 0.6 µm in width.