Active capsule for sampling intestinal liquid biopsy for microbiome analysis

Abstract:
Due to the importance of gut microbiome in gut health, disruption of its composition (dysbiosis) can lead to serious gastrointestinal and psychoneurological health issues making it an important biomarker for gut diagnostics. For an optimal microbiome diagnostic assays, a local good quality sample of intestinal liquid is required. In this work, we envision a modular sampling capsule that consists of an actuator module and a control module. We designed, fabricated and validated the actuator module that can perform site-specific sampling with variable physicochemical properties of chyme. The actuator module comprises an opening mechanism based on a meltable wax valve (melting temperature 61 °C) with integrated microheater, a closing valve based on swellable cellulose membrane, a filter membrane, and an evacuated sampling chamber with integrated dried preservative material. When tested with a diluted stool sample (330 mg/mL), the opening valve opened within 3.6 ± 0.5 seconds after microheater activation at 120 ± 10 mA. The temperature reached within 20 seconds was measured to be 101 ± 4 °C. The diluted stool sample was filtered through the integrated filter membrane and aspirated into the sampling chamber within 1-2 seconds (sampling delay time). The closing valve closed completely within 10 min, after its contact with the stool sample.