Modeling and Optimal Design of High-Sensitivity Piezoresistive Microcantilevers Within Flow Channels for Biosensing Applications

摘要

The mechanical design and optimization of piezoresistive cantilevers for biosensing applications is studied via finite element analysis. Models are described for predicting the static behavior of cantilevers with elastic and piezoresistive layers for analyte-receptor binding. The high-sensitivity cantilevers can be used to detect changes in surface stress due to binding and hybridization of biomolecules. The silicon-based cantilevers have thicknesses typically on the order of a few microns and are doped to introduce their piezoresistive characteristics. Parametric modeling based on the finite element method is used to help determine the optimum parameters of cantilever design. Chemo-mechanical binding forces have been analyzed to understand issues of saturation over the cantilever surface. Furthermore, the introduction of stress concentration regions during cantilever fabrication has been discussed which greatly enhances the detection sensitivity through increased surface stress. The spring constant and the resonance frequency change are also analyzed.