A microfabricated piezoelectric transducer platform for mechanical characterization ofcellular events

Abstract

During the last decade, it was discovered that the mechanical properties and interactions ofcells and their surrounding extra-cellular matrix play important roles in cellular activities.Substantial efforts have been made to develop various methodologies and tools to study cellmechanics. In this paper, we report an ongoing study on integrating the concept ofa smart structure with a microfabricated thin film piezoelectric transducer forcharacterizing the various changes in mechanical properties associated with cellularevents. A microbridge sensor integrated with a thin film piezoelectric transducerwas created from silicon dioxide and zinc oxide sandwiched between two goldelectrodes. The cells to be tested were cultured on the microbridge surface. Thesurface tractions exerted by the cells on the microbridge directly modulated theselected resonant behaviors, which were detected with the custom designed effectivesurface electrode. Our theory and simulation results showed, for the first time,that the application and changes in these surface tractions resulted in resonantand anti-resonant frequency shifts in the impedance response of the piezoelectrictransducer. Both spatial and temporal information of dynamic cellular activitiescould be inferred from the changes in the impedance spectra. The design, theory,finite-element simulation, microfabrication techniques, and preliminary test results arediscussed.