Calculation of Stress And Deflection In Double Layer Microcantilever For Biosensor Application

In microcantilever-based biosensor, a sensitive layer plays an important role as a place for the establishment of functional layer for detecting molecules target. When a sensitive layer is coated on the microcantilever surface, a surface stress change is induced as a consequence of adsorbate-surface interaction, resulting in a deflection of the microcantilever. However, the microcantilever with the sensitive layer of gold (Au) or 3-Aminopropyltriethoxysilane (aminosilane) which are commonly used in biosensor, has not been reported. In this paper, we study a dependence of the microcantilever deflection on the gold / aminosilane layers thickness in static mode operation. From a derivation of Stoney equation, it is found that the influence of material properties on the deflection of double layer microcantilever from the film stress and radius of curvature. Such relationship is important because the microcantilever deflection directly influences the sensor sensitivity. Our results indicate that the material and the thickness of sensitive layer should be considered to obtain a high sensitivity of microcantilever sensor.