Event

PhD Dissertation Defense: Michael Straker

Tuesday, September 23, 2025
10:00 a.m.-12:00 p.m.
AJC 5104
Debbie Chu
301 405 8268
dgchu@umd.edu

Title: LOW-POWER INGESTIBLE SAMPLING TECHNOLOGIES FOR TARGETED GASTROINTESTINAL TISSUE BIOPSY

Committee members:
Dr. Reza Ghodssi, Chair
Dr. William Bentley
Dr. Katharina Maisel
Dr. Ian White
Dr. Ryan Sochol, Dean's Representative

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 by a medical professional but also carries risks associated with the sedation. Additionally, endoscopes have a limited range of operation within the GI tract making remote areas such as the small intestine inaccessible. Ingestible capsule devices have emerged as a promising technology for overcoming the limitations of endoscopic biopsy, however, the current capsule designs suffer from key shortcomings that impede practical application. The devices designed for tissue resection utilize power consuming actuation mechanisms, require active operation by a medical professional, or cannot collect tissue samples of suitable quality for useful characterization. This work shows 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) hybrid fabricated biomimetic structures for enhanced capsular biopsy, (2) ingestible actuation devices for tissue collection, and (3) region responsive packaging technologies and sensing systems for site targeting. Specifically, biomimetic barbed biopsy punches and scrapers were developed for enhanced tissue collection. The structures featured internal barbs for tissue anchoring as well as microscale sharp edges to increase tissue penetration. The tissue collection devices were integrated with thermomechanical actuation modules capable of pushing them into tissue and bringing them back into the capsule for storage. These modules featured innovative designs that reduced the power requirement to achieve deployment with ingestible electronics. Targeting components were developed utilizing pH and water-soluble polymer materials to package actuators to be protected and selectively released in the small intestine. Additionally, an electrochemical sensing capsule was developed demonstrating the first luminal serotonin sensing capsule. These technologies give way to a new generation of autonomously acting ingestible devices for GI health monitoring and research.