A tactile sensing capsule endoscope employing force sensing cantilevers for tumor diagnosis in the GI tract

Abstract

The correlation between tissue elasticity and histopathological diagnosis has brought attention to the development of biomedical devices for in-vivo measurement of tissue biomechanical properties. Towards this aim, we have developed a tactile sensing capsule endoscope to measure tissue Young’s modulus, in situ. Inspired by force microscopy, the capsule comprises four cantilevers that probe the walls of the GI tract using a single miniaturized actuator. The force exerted on the cantilever tip by the tissue is measured using the piezoelectric layer integrated on the cantilevers. The tactile-based modulus sensing capsule was initially tested on ex-vivo animal tissue, followed by healthy and cancerous human specimens. The results clearly delineate the differences in mechanical properties, with a Young’s modulus of 11.3 ± 2.3 kPa for healthy and 26.8 ± 4.6 kPa for cancerous tissue. Overall, in the realm of tactile-based modulus sensing of tissues, our technology uniquely combines localized, quantitative Young’s modulus measurements with the capability to perform multiple measurements throughout the GI tract wall in a single procedure. Moreover, the developed sensor has a compact form factor, in accordance with the capsule dimensions, and simple manufacturing steps using stereolithography. With further improvements, the developed medical device can be utilized as a non-invasive diagnostic tool in the clinic.