Silicon Cantilevers and Quartz Crystals as Resonant Sensors for Biological Applications

S.J. O'Shea, Y.P Liew, X.D. Su, C.C. Dai, J. Zhang, I. Rodriguez, P. Lu*, and F. Shen*

Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602

*Institute of High Performance Computing, 89C Science Park Drive, 02-11/12 The Rutherford, Singapore 118261

Sensors based on the principle of resonance frequency change have potential applications as detectors in the chemical and biological fields. In this talk we discuss research on the detection of biological samples from liquid analytes. Two types of resonant sensor are discussed, namely silicon cantilever beams and quartz resonators. A description of our methodology will be given and data presented for adsorption (e.g. of IgG and simple thiol compounds) onto silicon cantilevers. Analytical and finite element modelling have been undertaken for the cantilever sensors to study the shifts in resonance response due to thermal effects, adsorption induced surface stress, and quality factor changes for fully or partially coated levers. Given the potential problems of temperature drift and sensor actuation in silicon cantilever structures we have begun studies into the use of quartz resonators. Results will be presented showing preliminary biological detection using sensor arrays microfabricated in AT-cut quartz and quartz tuning forks.