An implantable all-Parylene liquid-impedance based MEMS force sensor

We present a new transducer paradigm based on the electrochemical impedance transduction capability of encapsulated liquids within Parylene-based MEMS structures. We demonstrate the ability to measure forces in the micronewton range with a resolution of 4.56 m¿/¿N. These sensors are ideally suited for applications requiring highly sensitive interrogation of soft non-planar surfaces in wet environments. Specifically, in situ and in vivo measurement of interfacial forces exerted on tissue by chronically implanted neural prosthetic devices is presently an unmet engineering challenge. Our approach enables, for the first time, interrogation of such biomechanical phenomena.