Design of Small Mechanical Devices for Gut Sampling

The gut microbiome, a complex ecosystem of microorganisms in our gastrointestinal (GI) tract, plays a vital role in our health and is linked to various diseases such as obesity and Chron's disease. By thoroughly investigating the makeup and functionality of this microbial community, we can unlock new possibilities for targeted health interventions and treatments. However, the current methods for collecting microbial samples for gut studies, such as fecal sampling and endoscopy, tend to be either imprecise or highly invasive. This thesis presents a swallowable 3D-printed device designed to collect microbial samples from targeted GI regions. The device relies on peristaltic movement for GI transit and performs the sampling process without relying on electronic interfaces. It features millimeter-sized apertures that allow GI fluid to wick inside. The fluid dissolves a water-soluble element that triggers a sealing mechanism to close the apertures and protect the collected sample from contamination. Once egested, the device can be recovered, and its contents can be analyzed to determine microbiota composition. Initially, the device was designed to sample gastric juice, and its functionality was evaluated in both laboratory settings and animal models. The evaluation included sampling performance, mechanical reliability, biocompatibility, sample stability, and interactions between sample and device components. By utilizing the variation in pH in the different GI compartments, a later version of the device was coated with a pH-responsive polymer in varying layers to allow the collection of intestinal fluid at different intestinal regions. Additionally, the device was assessed for large-scale production, and its suitability for molding techniques was shown through a proof-of-concept compression molding process. The proposed device offers a new opportunity for non-invasive and precise characterization of the gut microbiota across the entire GI tract. This could contribute to significant advancements in gut microbiome research.