Goal: To enhance existing commercially-available passive capsule endoscopes used by clinicians to diagnose diseases in the small intestine. The first stage of this project is to allow the clinician to control the progress of the capsule along the patient's gastrointestinal tract instead of relying on the body's peristaltic contractions for device propulsion. This is accomplished by using bio-inspired adhesives to stick the capsule to the intestinal lining.

Approach: This work is focused in two primary areas: design and development of the capsule itself and biomechanical modeling of the intestinal environment. Key elements of the capsule design are actuator selection and adhesion design. In our current prototype, shape memory alloy is used to actuate legs coated with wet or dry micro-patterned PDMS arrays which are inspired by the sticking methods of certain beetles. The legs are pressed into the intestine wall to hold the capsule in place. Once reliable sticking of the capsule is achieved, work on controlling the locomotion of the capsule will begin.

Constitutive models of the intestinal tissue are being developed through biomechanical tissue testing. This provides an understanding the interaction between the forces generated by the capsule legs and tissue deformations to improve the effectiveness and safety of deployment.

Benefits: Current passive capsule endoscopes are equipped with cameras to image the gastrointestinal tract and provide reliable disease diagnosis in a minimally invasive way. However, because clinicians have no control over the position and orientation of the capsules, there is a chance for missed diagnoses. Allowing the clinician to stop, move and orient the capsule on command would improve diagnostic capabilities by letting the operator take a closer look or backtrack to reexamine a region of interest. Furthermore, once reliable control is obtained, to increase the capabilities of the device, the capsule can be equipped with tools for performing tissue biopsy or for cleaning or cauterizing wound sites.

Members: Paul Glass, Eugene Cheung, Metin Sitti

Papers:
P. Glass, M. Sitti, and R. Appasamy. A New Biomimetic Adhesive for Therapeutic Capsule Endoscope Applications in the Gastrointestinal Tract. Gastrointestinal Endoscopy, 65(5), p. AB 91, Apr. 2007.

M.E. Karagozler, E. Cheung, J. Kwon, and M. Sitti. Miniature endoscopic capsule robot using biomimetic micro-patterned adhesives. IEEE / RAS-EMBS international conference on biomedical robotics and biomechatronics. Pisa, February 2006.

E. Cheung, M.E. Karagozler, S. Park, B. Kim, and M. Sitti. A new endoscopic microcapsule robot using beetle inspired microfibrillar adhesives. Proceedings of the IEEE/ASME international conference on advanced intelligent mechatronics, 551-557, Monterey, July 2005.

J. Kwon, E. Cheung, S. Park, and M. Sitti. Friction enhancement via micro-patterned wet elastomer adhesives on small intestinal surfaces. Biomedical Materials, 1:216-220, 2006.