Polymeric cantilever-based biosensors with integrated readout

The authors present an SU-8 cantilever chip with integrated piezoresistors for detection of surface stress changes due to adsorption of biomolecules on the cantilever surface. Mercaptohexanol is used as a model biomolecule to study molecular interactions with Au-coated SU-8 cantilevers and surface stress changes of about 0.1 N/m are observed. The measurements indicate that the SU-8 surface is inert to mercaptohexanol molecules, which enables the use of a bare SU-8 cantilever as a reference. Moreover, the sensitivity of the cantilevers to pH changes is presented. The results demonstrate that SU-8 cantilevers are a promising alternative to Si-based cantilevers. (c) 2006 American Institute of Physics.