Hybrid Hydrogel-Magnet Actuated Capsule for Automatic Gut Microbiome Sampling.

Area of Science:

• Biomedical Engineering
• Gastroenterology
• Materials Science

Background:

• Pill-sized capsules offer non-invasive intestinal fluid sampling for gut microbiome studies.
• Integrating automatic sampling and active locomotion in capsules is challenging due to space limitations.

Purpose of the Study:

• To develop a novel hybrid hydrogel-magnet actuated capsule for site-specific gut microbiome sampling.
• To achieve automatic fluid sampling triggered by pH changes and active locomotion via magnetic fields.

Main Methods:

• Fabricated two capsule designs (A: 31 μL, B: 41 μL) with pH-responsive hydrogels.
• Tested automatic sampling in simulated gastric and intestinal fluids.
• Evaluated active locomotion using an external rotating magnetic field and performed seal tests.

Main Results:

• Automatic sampling occurred in simulated intestinal fluid within 6-15 hours.
• Active locomotion (rotation, rolling, tumbling) was achieved at 10 mT magnetic field.
• Oil piston seals proved superior to water seals for contamination mitigation.

Conclusions:

• The developed capsule successfully integrates multi-functionality (sampling and locomotion) in a compact design.
• This technology eliminates the need for onboard electronics or external triggers for capsule sampling.
• The capsule shows promise for advancing gut microbiome research in nutrition and chronic diseases.