Development of a therapeutic capsule endoscope for treatment in the gastrointestinal tract: Bench testing to translational trial

Video capsule endoscopy is a widely accepted clinical alternative to conventional endoscopy for examination of the gastrointestinal tract. Its advantages are that it can visualize the entire gastrointestinal tract including the anatomically remote small intestine and it is less invasive for the patient as compared to conventional endoscopy. However, video capsule endoscopy is suitable only for diagnosis, with little research into therapeutic capsule endoscopy. Like video capsule endoscopy, therapeutic capsule endoscopy has great potential to reach locations that would previously have been difficult, such as the small intestine. Ultrasound-mediated targeted drug delivery is a promising therapeutic capsule based modality as it may be scaled to size, provides temporary gut barrier disruption and power requirement is relatively low. This paper investigates the feasibility of a therapeutic capsule endoscope utilizing ultrasound-mediated targeted drug delivery. A prototype device, SonoCAIT, was built and tested. Further investigation of the drug delivery capabilities of the miniature focused US sources, testing was carried out on an in vitro model replicating the lining of the small intestine. This involved measuring the transepithelial resistance, a measure for barrier function, during insonation. A drop in transepithelial resistance occurred during insonation and returned to starting value post insonation. In anticipation of in vivo work, SonoCAIT, was reconfigured to operate within the small bowel of pigs.