A micrometer-sized cantilever can be used as a very sensitive biochemical sensor in ambient and aqueous environment. Basically, a biochemical reaction at the cantilever surface can be monitored as a bending of the cantilever due to a temperature change or due to a change in the surface stress. The temperature change is observed by coating one side of the cantilever with a metal layer. As a result, the cantilever will bend due to the bimetallic effect. Furthermore, a change in mass load can be detected as a change in the resonant frequency of the cantilever. In order to detect biochemical reactions at the cantilever surface, one side of the cantilever has to be coated with a 'detector film' that reacts with the biomolecules under investigation. This novel, cantilever-based detection technique has proven very sensitive. The cantilever-based sensors have a huge potential, especially in the field of biochemical analysis. The detection technique can be used to construct smarter and simpler biochemical detectors, but it should also allow novel studies of single molecular interactions due to the extremely high mechanical sensitivity of microcantilevers.
