Thermal biosensors from micromachined bulk acoustic wave resonators

A micromachined Y-cut quartz resonator based thermal biosensor - configured with a reaction chamber that is physically separated but located in close proximity to the resonator for sensitive calorimetric biosensing applications is presented. The coupling of heat from the reaction chamber to the quartz resonator is achieved via radiation and conduction through ambient gas. This configuration of the sensor allows for a very robust sensing platform with no fouling of the sensor surface or degradation in its performance metrics. Frequency based and Impedance-based tracking of resonance frequency was used for chemical and enzymatic activity measurements and compared here. An impedance sensitivity of 852 Ω/°C (frequency sensitivity of 7.32 kHz/°C) was obtained for the 91 MHz.