Design and Analysis of a Distributed-Deflection Sensor With a Built-In Probe for Mechanical Measurement of Soft Tissues With Curved Surface

Abstract

This paper presents a theoretical analysis of using a distributed-deflection sensor with a built-in probe for mechanical measurement of soft tissues with curved surface. The core of the sensor is a rectangular polydimethylsiloxane (PDMS) microstructure with a built-in probe on its top and an electrolyte-enabled resistive transducer array at its bottom. Upon being pressed against a tissue region, the built-in probe assists in avoiding extrusions and generating deformations necessary to conform to the curved surface of the tissue region. Consequently, the true mechanical properties of the tissue translate to the spatially distributed deflection in the microstructure, which registers as resistance changes by the transducer array. A simplified 1D theoretical model is created and utilized for correlating the design parameters of the sensor and the probe to the tissue parameters, in order to meet three performance criteria for the tissue-probe-sensor interaction in measurement. Costal cartilage tissues are chosen as the tissue example for analysis. The analyzed results provide the design guideline for the numerical analysis in the future for accurate determination of the design parameters for soft tissues of interest.