The authors report the design, fabrication, and in vivo validation of a miniaturized ingestible microdevice (7 × 2.7 mm) that enables site-specific sampling of luminal microbiota and protein biomarkers in the upper gastrointestinal (GI) tract, overcoming limitations of conventional fecal sampling and invasive techniques. The device integrates an enteric-coated gelatin cap that remains intact in gastric pH (≈ 1–1.5) and dissolves at intestinal pH (≈ 3–5), exposing an inlet that permits luminal fluid entry into an activation chamber. A polyacrylate hydrogel bead in this chamber swells upon contact with intestinal fluid to seal the inlet, preventing cross-contamination and isolating the collected sample. The authors used stereolithography 3D printing for precise microdevice fabrication and characterized the hydrogel swelling kinetics and inlet closure dynamics in vitro. In Sprague–Dawley rats (n = 5), oral administration demonstrated autonomous pyloric transit without tissue injury or inflammation, and retrieved devices yielded ~13.5 ng genomic DNA, sufficient for 16S rRNA gene sequencing that revealed site-specific microbiota profiles distinct from fecal samples. Concurrent measurement of intestinal alkaline phosphatase (~6.5 µg mL⁻¹) confirmed dual microbiome–biomarker sampling capability, establishing a non-invasive platform for longitudinal microbiome profiling and species-level microbial identification with potential future application in larger animals and humans.
Source : https://onlinelibrary.wiley.com/doi/10.1002/smll.202510289
