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A facile fabrication process for bulk PZT microsystems using dry film photoresist and micro powder blasting is presented. Bulk PZT and dry film photoresist etching characteristics are evaluated as a function of process parameters and mask dimensions using 127 μm thick PZT substrates. The resulting process simplifies microscale patterning of bulk PZT compared with existing methods, with selection of suitable etching parameter providing excellent etch rate, selectivity and anisotropy. The technique is used to fabricate two different cantilever microactuator topologies based on piezoelectric d 31 and d 33 mode actuation, demonstrating the capabilities of the patterning method for applications in bulk PZT microelectromechanical systems (MEMS).

A sensitive and rapid impedemetric immunosensor is demonstrated utilizing porous volumetric microfluidic detection elements and silver enhanced gold nanoparticle probes. The porous detection elements significantly increase capture probe density and decrease diffusion length scales compared to conventional planar sensors to improve target capture efficiency and enhance impedance signal. In this work, a packed bed of silica beads functionalized with antibody probes serves as a porous sensor element within a thermoplastic microchannel, with an interdigitated gold electrode microarray used to measure impedance changes caused by the concentration dependent formation of silver aggregates. The measured impedance change is independent of electrode spacing, enabling a device with low resolution electrodes to achieve a sandwich immunoassay detection limit between 1–10 ng/mL with a 4-log dynamic range, with a total assay time of 75 min.

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A new class of miniature monolithic piezoelectric transformer that leverages a simple two-mask bulk piezoelectric microfabrication process is presented. A millimeter-scale transformer design based on a disk-shaped resonator topology with annular electrodes is fabricated to produce step-up voltages in a compact form factor. The radial vibration characteristics and voltage gain of the bulk transformers under varying impedance loads have been analyzed experimentally, and compared against an electromechanical model of transformer performance. A maximum voltage gain of 7.3 was obtained.