LOW-POWER INGESTIBLE SAMPLING TECHNOLOGIES FOR TARGETED GASTROINTESTINAL TISSUE BIOPSY

Abstract

The prevalence of gastrointestinal (GI) disorders has driven a need for medical screening for chronic conditions like celiac disease, inflammatory bowel disease, and GI cancers. The standard screening method for GI health conditions is endoscopic biopsy where a medical professional visually surveys the bowel for suspected pathological tissue and resects a sample for further analysis. This method is not only costly due to the need for operation requiring a medical professional but also carries risks associated with sedation. Additionally, endoscopes have a limited range of operation within the GI tract, making remote regions, such as the small intestine, inaccessible. Ingestible capsule devices have emerged as a promising technology for overcoming the limitations of endoscopic biopsy, yet current capsule designs suffer from key shortcomings that impede practical application. The capsules designed for tissue resection rely on power-intensive actuation mechanisms, require active operationby a medical professional, or cannot collect tissue samples of suitable quality for useful characterization. This work presents the development of actuation, packaging, and targeting technologies toward a feedback-triggered ingestible capsule for sampling tissue in remote regions of the GI tract. This dissertation addresses the development of (1) region-responsive packaging technologies and sensing systems for site targeting, (2) hybrid fabricated biomimetic structures for enhanced capsular biopsy, and (3) ingestible actuation devices for tissue collection. Specifically, localization technologies were developed utilizing pH and water-soluble polymer materials to package actuators to be protected and selectively released in the small intestine. Further, capsule electronics were integrated with an electrochemical sensor, enabling localization via analyte detection in the 2-10 μM concentration range. Biomimetic barbed biopsy punches and scrapers were developed for enhanced tissue collection. The structures featured internal barbs for tissue anchoring and microscale sharp edges to increase tissue penetration. The tissue collection devices were integrated with thermomechanical actuation modules capable of collecting tissue samples of 1.5-6.7 mm3, suggesting clinical viability. These modules featured designs that reduced power requirements to 138–150 mW while enabling remote activation from ingestible electronics. Together, these advances establish a foundation for autonomous ingestible biopsy capsules, facilitating minimally-invasive GI diagnostics that extend to regions unreachable by current methods.