Ultrasensitive wireless quartz crystal microbalance bio/gas sensors

Abstract

Quartz-crystal-microbalance (QCM) sensor can detect various physical and chemical properties, including biomolecules, gasses, external forces, and so on, through the change in its resonant frequency. Because of extremely high temperature stability of the resonant frequency, no thermostatic device is required, making the entire system compact. The sensitivity is governed by the thinness of the quartz resonator, and the wireless-electrodeless approach has achieved much thinner resonators. This review introduces recent advances in the wireless-electrodeless QCM sensors for studying real-time biomolecules and target-gas detection.

Sensitivity enhancement of hydrogen-gas sensor by sub nm Au on Pd surface of a wireless quartz resonator

“…Previously, we coated a Pd film on AT-cut quartz resonators with thicknesses of 10-26 μm. 56) When H 2 is absorbed, the Pd film expands on one side, leading to bending deformation of the resonator and a decrease in the resonance frequency. 57) From the change rate of the resonance frequency in a 10 μm thick resonator embedded in a micro-electromechanical system chip, we detected less than 10 ppm H 2 at room temperature within a response time of 5-100 s. 58) The detection limit of the 26 μm thick resonator was less than 1 ppm at 55 °C, but the sensor does not operate at room temperature.…”