LTCC microreactor for urea determination in biological fluids

This article presents design, fabrication and testing of an enzymatic microreactor with integrated heater and a temperature sensor. The microsystem was fabricated using low temperature co-fired ceramics (LTCCs) technology, which has a few advantages over silicon-based fabrication processes. Computational fluid dynamics (CFD) and finite element method (FEM) analysis was used to arrive at an optimum microreactor and heater design. The heater performance was evaluated using thermographic measurements, and the temperature resistance characteristics of the temperature sensor revealed good electrical properties and stability at higher temperatures (up to 140 °C). As an enzyme carrier, the glass beads coated with polyacrylonitrile layer and porous glass beads were used. The microreactor was used to measure urea concentration with high output signal (ca. 2.5 pH units) and large scale. The maximal output signal enabled to apply presented microreactor for determination of urea in biological or environmental fluids. The properties of the LTCC-based enzymatic microreactor were comparable with the features of a similar one made in silicon.