Mucosa-Interfacing Capsule for In Situ Sensing the Elasticity of Biological Tissues

Monitoring the elasticity of soft biological tissues in the gastrointestinal (GI) tract with minimal invasion holds promise for early diagnosis of intestinal fibrosis, colorectal cancer, and other diseases featuring abnormal elasticity. However, existing methods of sensing tissue elasticity have drawbacks such as insufficient resolution for elastography, and discomfort or the requirement of risky anesthesia for flexible endoscopes or implantable devices. Here a wirelessly actuated palpation mechanism is presented, integrated into a swallowable capsule device, offering in situ tissue elasticity measurement with minimal invasiveness. The approach employs a magnetic soft cantilever beam actuated by external magnetic fields to gently press against soft tissues. Mechanical stress and strain are monitored by an onboard magnetic sensor and a strain gauge, allowing for an accurate assessment of tissue elasticity. Additionally, wireless modules utilizing Bluetooth Low Energy (LE) and powered by a battery facilitate real-time communication. The device operates under external magnetic field control, which can move freely over soft tissues during examinations and palpate suspicious areas. The elasticity sensing mechanism is validated and assessed on both phantom structures and ex vivo porcine colon tissues. The capsule device holds significant promise for assessing tissue physiological conditions and facilitating early disease diagnosis in hard-to-reach areas of the body.