Mems capacitive force sensors for micro-scale compression testing of biomaterials

This paper reports on recently developed MEMS capacitive force sensors and their application to micro-scale compression testing of hydrogel microcapsules for drug delivery. The bulk microfabricated capacitive force sensors are capable of resolving forces up to 165 muN and a resolution of 33.2 nN along two independent axes. Employing tri-plate differential comb drives and a two-frame design, the sensors demonstrate a high input-output linearity and suppressed cross-axis coupling. The MEMS capacitive force sensors have been applied to the quantification of mechanical parameters (Young´s modulus and coefficient of viscosity) of individual drug-delivery microcapsules through micro-scale compression testing.