A High-Order Membrane Resonator as Density-Viscosity Sensor for Sweat Analysis

This paper demonstrates the potential application of a high-order membrane resonator as a density-viscosity sensor for sweat analysis. The resonator shows a sensitivity of $\sim$93kHz/cp to viscosity change, a sensitivity of $\sim$93kHz/(g/c$\mathrm{m}^{3}$) to density change, and a sensitivity of 0.2448 kHz/(g/L) to salinity change for a liquid of around 1 cp viscosity, 1 g/c$\mathrm{m}^{3}$ density and 0. 9g/L salinity, mimicking physical properties of the sweat. The resonator has also been used for gravimetric sensing of chemical gases, such as a sub-ppm resolution ammonia sensor, which will generate more diagnostic information from sweat analysis.