Gear Train-Enabled Low-Power Thermomechanical Biopsy System for Ingestible Capsules

This paper reports the first successful demonstration of a gear train-enabled low-power thermomechanical biopsy system for ingestible capsules. The biopsy module utilizes a torque-loaded 3D-printed gear train and collection tool to scrape the GI mucosa to be stored in the capsule body. Actuation is triggered by a microfabricated thin film heater using 36–42 mA of instantaneous current draw and a power of 138 mW. The module produced 1.6±0.7 N (mean ± SEM, n=5) of force to collect a sample volume of 19±8.0 mg from agarose tissue phantoms. Sample volumes collected are compatible with polymerase chain reaction (PCR) for genetic biomarker detection. The device's low-power operation allows integration with onboard electronics, activation by a single ingestible-sized battery, and the future development of a wireless ingestible capsule for tissue sampling.