Ovenized Dual-mode Piezoelectric MEMS Resonator for bovine serum albumin (BSA) sensing

Piezoelectric MEMS resonators have been increasingly employed in various biosensing applications owing to their low cost, compactness, and ultra-high sensitivity. In this article, we demonstrate the use of an ovenized dual-mode solidly mounted resonator (SMR) for sensing bovine serum albumin (BSA). The ovenized SMR is capable of achieving fixed, elevated temperatures using a micro-heater embedded beneath the structure. Therefore, these ovenized resonators can be used for obtaining thermally modulated device response resulting in enhanced sensitivity. This enables high-sensitivity detection of BSA as the adsorption of BSA increases at elevated temperatures due to thermally-induced conformational changes of molecules. In this study, the SMR-based biosensor exhibited a sensitivity of -62 ppm/μg/mL for a BSA concentration of 50 μg/mL without ovenization (at room temperature of 25
^°
C). Whereas, in the ovenized device where an elevated temperature of ~36.2
^°
C was achieved by supplying the micro-heater 200 mW the sensitivity observed was -192 ppm/μg/mL for the same BSA concentration. This indicates that the ovenized devices exhibit approximately 3x improved sensitivity due to higher adsorption of BSA at elevated temperatures.