Novel MEMS stiffness sensor for in-vivo tissue characterization measurement

This paper presents the design, mathematical model, fabrication and testing of a novel type of in-vivo stiffness sensor. The proposed sensor can measure both tissue stiffness and contact force. The sensing concept utilizes multiple membranes with varying stiffness and is particularly designed for integration with minimally invasive surgical (MIS) tools. In order to validate the new sensing concept, MEMS capacitive sensors are fabricated using surface micromachining with each fabricated sensor having a 1 mm times 1 mm active sensor area. Finally, the sensors are tested by touching polymers of different elastic stiffnesses. The results are promising and confirm the capability of the sensor for measuring both force and tissue compliance.