Electronic-free Traceable Smart Capsule for Gastrointestinal Microbiome Sampling

Authors: NEJATI, SINA - Purdue University; SARNAIK, DEVENDRA - Purdue University; GOPALAKRISHNAN, SARATH - Purdue University; KASI, VENKAT - Purdue University; KRISHNAKUMAR, AKSHAY - Purdue University; HYDE, SAMUEL - Purdue University; MCCAIN, ROBYN - Purdue University; PARK, KINAM - Purdue University; Johnson, Jay; RAHIMI, RAHIM - Purdue University

Submitted to: Advanced Materials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2023
Publication Date: 1/31/2023
Citation: Nejati, S., Sarnaik, D., Gopalakrishnan, S., Kasi, V., Krishnakumar, A., Hyde, S., Mccain, R., Park, K., Johnson, J.S., Rahimi, R. 2023. Electronic-free Traceable Smart Capsule for Gastrointestinal Microbiome Sampling. Advanced Materials. https://doi.org/10.1002/admt.202300810.
DOI: https://doi.org/10.1002/admt.202300810

Interpretive Summary: A non-invasive assessment of intestinal microbiome in pigs could reduce the number of animals used in research and eliminate the need to euthanize animals for intestinal microbiome measures. Therefore, the study objective was to design and evaluate a non-electric and traceable smart capsule designed for repeated microbiome sampling in pigs. It was determined that the intestinal sampling bolus could be effectively traced within the gastrointestinal tract of pigs, which would allow for improved detection upon natural passage of the device. Results from this study will be used to further improve the capsule design and allow for more widespread use to improve swine welfare under research conditions.

Technical Abstract: Non-invasive smart passive sampling capsules have enabled the understanding of microbiome-disease state interactions in inaccessible GI regions. However, due to the variance in patient motility, confusion among physicians may arise regarding whether the capsule travels naturally through the GI tract or is lodged. Therefore, a quick and simple method to determine the exact location of such capsules is imperative to assist the physician in understanding if further observation or surgical intervention is required. Thus, to aid with the device location detection, a previous passive sampling capsule platform was modified to integrate a metal cylinder tracer to facilitate portable, rapid, and simple metal detection using a handheld metal detector and more accurate localization using X-ray radiography. As a result, a systematic study was conducted to identify the optimal length and choice of material for the best omnidirectional detectability of the capsule using both readout systems. The results of these investigations showed that the SS 316L cylinder with an optimized length (12 mm) provided the necessary omnidirectional detection and tracing while also exhibiting minimal toxicity and good corrosion resistance properties throughout the relevant physiological conditions in the GI tract. A series of in vitro tests were performed to study bioinert properties, the metal cylinder's corrosion resistance, and the sampling capsule's detectability with the integrated metal tracer using a metal detector and X-ray radiography. Further in-depth in vivo studies were also validated on pig models to determine the effectiveness of capsule localizations throughout the GI tract using both systems.