Chapter 22
Microcantilever Sensors
Microcantilevers belong to the class of microelectromechanical devices that encompass all those devices produced by microfabrication except integrated circuits [1]. When integrated with a sensing element, a microcantilever responds to the recognition event by mechanical deformation. An alternative mechanical transduction method utilizes cantilevers that vibrate at the resonance frequency. In this case, the mass change produced by the recognition event induces a change in the resonance frequency.
Microcantilevers with a sharp tip were originally introduced as probes for exploring solid surface topography by atomic force microscopy in the early 1980s. It was soon realized that microcantilevers are sensitive to physical parameter such as temperature and humidity. By the mid-1990s, it was demonstrated that cantilevers modified with chemically sensitive layers respond selectively to particular chemical compounds. This opened the way to the development of a new class of chemical sensor in which the transduction is based on the mechanics of elastic solids. Despite its relatively recent introduction, this field of research has already produced very promising results. Early results obtained in the microcantilever sensor area have been summarized in refs. [2, 3]. A good introduction to the field is given in ref. [4]. The mechanical principles of microcantilever operation are reviewed in [5, 6], while comprehensive overviews of fabrication methods and recent ...
