Elastometric sensing using higher flexural eigenmodes of microcantilevers

We present a method to detect with high sensitivity the viscoelastic property changes of sensor coatings on microcantilever arrays due to radiation, analyte binding, or adsorption. The method uses higher order flexural eigenmodes to identify the location and magnitude of the nonuniform elasticity changes in the microcantilever coating. We demonstrate the method by monitoring the time evolution of resonance frequencies and Q factors of different flexural eigenmodes of microcantilevers functionalized with a small drop of a photosensitive polymer as it is exposed to ultraviolet radiation. The method is particularly well suited for measuring quantitatively the time varying viscoelastic properties of thin films or biological materials attached to microcantilevers. (C) 2007 American Institute of Physics.