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A smart capsule with a bacteria- and pH-triggered enteric polymer coating for targeted colonic microbiome sampling
Devendra Sarnaik1, Akshay Krishnakumar2, Sina Nejati1
1School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA; Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA.
Acta Biomaterialia
|April 22, 2025
Summary
A new non-invasive capsule uses a dual-trigger coating to precisely sample the colonic microbiome. This technology overcomes limitations of current methods, offering improved diagnostics for gastrointestinal diseases.
Area of Science:
- Gastroenterology and Microbiology
- Biomaterials Science
- Medical Device Engineering
Background:
- Conventional gut microbiome sampling methods (fecal analysis, colonoscopy) have limitations in site-specificity and invasiveness.
- Existing non-invasive sampling capsules struggle with colonic region targeting due to variable pH.
- Accurate colonic microbiome analysis is crucial for precision nutrition, medicine, and gastrointestinal disease management.
Purpose of the Study:
- To develop and validate a novel non-invasive capsule for targeted colonic microbiome sampling.
- To overcome the limitations of pH-only triggered capsules for colonic analysis.
- To enable precise microbial profiling for improved gastrointestinal health diagnostics and therapies.
Main Methods:
- Development of a dual-triggered polymeric enteric coating using lactulose and N,N-dimethylaminoethyl methacrylate.
- Characterization of polymer blends using Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, and Differential Scanning Calorimetry.
- In vitro and in vivo validation in a pig model, followed by 16S rRNA sequencing for microbial analysis.
Main Results:
- An optimized dual-layer coating demonstrated rapid (∼2 h) degradation in the colon across a pH range of 5-8, triggered by both bacteria and pH.
- The capsule successfully sampled the colonic microbiome in vivo, showing taxonomic similarity to the native colonic microbiota.
- The dual-trigger system ensured outer layer dissolution in the small intestine and inner layer dissolution in the colon.
Conclusions:
- The developed dual-triggered capsule offers an effective, non-invasive method for site-specific colonic microbiome sampling.
- This technology advances precision diagnostics for gastrointestinal diseases like inflammatory bowel disease and colorectal cancer.
- The findings support the potential for improved targeted therapies, dietary guidance, and biomedical research in gut health.
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