A micro‐machined piezoelectric sensor for monitoring viscosity‐variation.

Abstract

A micro‐machined piezoelectric sensor is developed for monitoring the viscosity‐variation in small amounts of liquid in real time. The device is initially devised for monitoring the state of polymerized chain reaction (PCR) of or ribonucleic acid and being integrated into a Lab‐on‐a‐chip (LOC) since the viscosity may increase with an increase in the amount of DNA with PCR. The sample fluid is assumed to be homogeneous so that the wave propagation characteristics in a micro‐channel can be used for measurement. The developed measuring technique is devised to be performed with a small amount of sample liquid and to be able to monitor the viscosity variation in real time. The developed device is composed of two chambers connected by multi‐micro‐channels and was fabricated using micro‐machining technology so that it can be fabricated with other components when it is integrated in LOC. Each chamber has a unimorphic piezoelectric diaphragm; one for generating and the other for sensing sound waves. From the feasi...