Squeezing through the gut : micro-manufacturing of smart capsule : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in the School of Food and Advanced Technology at Massey University, Palmerston North, New Zealand

Abstract

Capsule robotics has been an important part of medical evaluation of conditions within the Gastro-intestinal (GI) tract since their inception in 1957. As technology improved, their functionality expanded to explore the entirety of the GI tract such as; taking images; measuring chemical and mechanical properties; delivering drugs; performing biopsies; and retrieving samples of microbiome. This has led to a significant increase in adoption with over 130,000 procedures conducted annually; however, approximately 1,400 of these procedures result in capsule retention, which requires surgery to remove the capsule. This risk is significantly increased, with patients suffering from inflammatory bowel diseases such as Crohn’s disease being approximately 8 times more likely to retain capsules. This thesis investigates how to improve the safety and motility of microrobotic capsules, especially for those with intestinal complications, to ensure equal access to this technology and improve patient outcomes, increasing access to the information needed to better treat these ailments. This project covers multi-disciplinary subject areas ranging from biomedical technology, mechanical characterisation, robotics, and electronics. Including the design and manufacture of capsule exteriors down to the microscale and the development of new testing equipment for them, such as a synthetic intestine tensile testing platform and robotic intestine testing system for quantifying capsule performance inside an intestinal-like environment. In addition, a precise testing procedure is provided with the created equipment so that experiments can be easily replicated and accurate data are collected. The best capsule design determined is a three-dimensional resin printed capsule using surgical guide resin with a six-ridged segmented design. Determined using force response data from pulling capsule designs and measuring the excess power draw to push them through a synthetic intestinal con striction. This also demonstrated the functionality of the testing equipment developed during this research project. In the future, these capsule design considerations are expected to be used to increase the adoption of this field of technology and improve patient outcomes. Also, it is hoped the testing equipment is used and developed further by my research group to improve their respective project outcomes; and by any external group looking to test their capsule prototypes.