Development of a Swallowable, Long-duration Attachment Biosensor for the Small Intestine for Use in a Mobile Health Application

W Xie, BS1, W Lewis, BS1, Jennifer Jolley, MD2, Vishal Kothari, MD2, Benjamin Terry, PhD1, Dmitry Oleynikov, MD2. 1University of Nebraska Lincoln, 2University of Nebraska Medical Center

INTRODUCTION: We have developed a tissue attachment mechanism (TAM) that can be used to improve mobile health. This noninvasive TAM can safely and persistently adhere a small biosensor to the lining of the gastrointestinal (GI) tract. The presence of wearable sensors and actuators (and mobile health technology) has dramatically increased with the rise of mobile computing and communications. This field of technology has generated significant enthusiasm, in part because of the enormous challenges and cost of modern day health care. The GI tract is an ideal location for miniature biosensing systems for mobile health due to its large volume and surface area, proximity to vital organs, and because the mobile devices can be used to measure the caloric and nutritional contents of ingested food.

METHODS: A swallowable microrobotic capsule (developed in other work by our lab) delivers the TAM to a predetermined point in the small intestine where it adheres to the mucosal lining. As a component of a sensing system, the TAM will enable the collection of high-impact and accurate biometrics that are not feasible with current wearable technologies. The TAM was designed, optimized and tested for safety and adhesive capabilities in vitro on excised tissue and in vivo in a live pig model. Six TAMs were tested in the in vitro attachment tensile experiment. Each TAM was tested on three different proximal intestine tissue samples. The attachment strength was tested for 10 minutes using a sine wave pull force on the TAM with a peak value 0.4N and 6 second period, which represents typical human intestinal traction force from peristalsis.

RESULTS: The in vitro attachment tensile test verified that the tissue is not damaged nor perforated by the attachment process. In the in vivo experiment, four TAMs were placed in the intestine of a pig through individual longitudinal enterotomies. X-ray images were taken each hour after the surgery and showed zero migration of the TAMs after 16 hours of adhesion. Post experiment inspection confirmed the attachment did not cause visible damage to tissue.

CONCLUSIONS: These results confirmed the reliability of the TAM in vivo and demonstrated preliminary feasibility of long-term sensor adhesion to the GI tract. These results also demonstrate success of a key component of a new swallowable sensing system for long-term diagnostics and mobile health.

Figure (A) Microrobotic capsule with tissue attachment mechanism. (B) Prototype tissue attachment mechanism with X-ray marker to track migration. (C) Lateral abdominal radiographs showing four attachment mechanisms in vivo. (D) Attachment mechanism after 16 hours adhesion.

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