S. Sonkusale
Tufts University,
United States
Keywords: microbiome, ingestibles
Summary:
This talk will cover an exciting field of ingestibles specifically for studying the role of gut microbiome in health and disease. The author and his team have developed several platforms that can sample the gut microbiome, monitor gastrointestinal pH, and detect microbial pathogens in situ. First, we present a soft, autonomous, ingestible capsule designed for non-invasive sampling of the small-intestinal microbiome. The device features a 3D-printed elastic shell coated with an enteric layer that dissolves at small-intestinal pH. Multiple side-wall inlets open on arrival; a self-locking mechanism comprising swellable polyacrylate beads closes the inlets once luminal fluid has entered, thereby preventing contamination from downstream regions. Bench-scale and animal studies show that the bacterial populations collected by the pill closely resemble those sampled from the small intestine post-mortem, with higher diversity and lower concentration than stool-derived samples. Clinical relevance here lies in enabling spatially resolved microbiome analysis upstream of the colon, overcoming limitations of fecal sampling and enabling direct linkage of microbiome composition to small-intestinal physiology and pathology. Second, the team developed a modular ingestible pH-sensing capsule employing thread-based conductive sutures coated with carbon and polyaniline (PANI/C) as the working electrode. These smart threads are integrated with miniaturised front-end readout electronics in a 3D-printed capsule (~29 mm × 8.5 mm) capable of traversing the GI tract and logging local pH variations. Given that pH is a known biomarker for gastrointestinal disorders such as inflammatory bowel disease, this ingestion platform enables in situ monitoring of pH dynamics across stomach, small intestine, and colon. The modularity and thread-based architecture minimise fabrication complexity and support integration with additional sensing modalities. Finally, the most recent work extends the ingestible capsule concept to pathogen quantification: an ingestible sensor utilising fluorescent gold nanoparticles and molecularly-imprinted polymers on thread substrates for the localized quantification of Escherichia coli in the gastrointestinal tract. While still under development, this platform underscores the capacity to move beyond passive sampling to active biochemical interrogation of the gut environment. Across these three platforms—microbiome sampling, pH sensing, and E. coli detection—the unifying technical theme is the integration of flexible, low-profile sensing threads and micro-mechanical capsule architectures suitable for ingestion, with attention to biocompatibility, spatial targeting, and contamination control. Clinically, these devices promise to fill key gaps in gastrointestinal diagnostics: enabling access to regions upstream of the colon, providing continuous or spatially-resolved biomarker monitoring, and offering new windows into host–microbe interactions and pathogen dynamics. In this talk I will detail the engineering design, fabrication strategies, in-vitro and in-vivo validation, and potential translational pathways of these ingestible technologies.