Shape optimization of micromachined biosensing cantilevers

Microcantilever-based biosensors utilize micromachined cantilevers to detect the small mass changes due to affinity of analytes to their counterpart receptors. A biosensing cantilever with a higher frequency sensitivity will be able to identify a smaller mass variation, while a larger sensing area provides more opportunities for the receptors to react with the analytes. This paper presents the optimum shape designs, with objective functions incorporating both the sensitivity and the amount of sensing area, for two basic shapes of biosensing cantilevers: a single beam with a constant cross section and a V-shaped beam. Numerical examples show that the frequency sensitivities for the cantilevers with the optimum shapes are significantly improved for both types of cantilevers.