Some 3.1 million people in the U.S. suffer from chronic gastrointestinal (GI) autoimmune disorders like inflammatory bowel disease, Crohn's disease and ulcerative colitis. Medical science has made substantial advances in the last few decades, largely through “systemic” therapies like pills, injections and infusions. Unfortunately, as these therapies diffuse throughout the body, their effectiveness also diminishes. Medicine can’t be targeted to the inflammatory lesions that characterize these gut diseases, and the treatments produce substantial side effects. Capsules can perform GI imaging, gas sensing, lesion biopsy and drug delivery, and they can be commanded remotely through Wi-Fi and a phone app. Still, one problem has persisted: how to keep the capsule in place to deliver medicine amid the constant churning of the digestive system.

Now, researchers at the University of Maryland (College Park, MD, USA) have developed a futuristic new capsule that can be ingested, guided and activated to detect, monitor and treat chronic problems in the GI tract. The researchers have demonstrated a tiny spring actuator that can anchor the capsule, allowing it to deliver a drug deposit to planned locations in the GI tract. With the ability to stay in place for a sustained period of time, the capsule can deliver multiple doses of medication as needed.

The new research introduces the thermomechanical 3D-printable spring actuator, a mechanism that works with existing ingestible capsule-based sensing and communication technologies and enables treatment based on detected GI biomarkers and external commands, which can be delivered via Bluetooth. The actuator is combined with the first application of the Ghodssi’s biomimetic barbed microneedle technology, known as SMAD, for Spiny Microneedle Anchoring drug Deposit. When it’s time to deploy the spring and propel its payload of therapeutic drugs, the capsule’s tiny resistive heating element melts a material called polycaprolactone that holds it in place. The SMAD is then released from the spring to provide prolonged dissolving therapeutic drug delivery to specific lesions.

“Our innovation is an early example of using hybrid fabrication approaches that merge 3D printing with traditional microfabrication to create new and impactful devices,” said first author Joshua Levy, a materials science and engineering doctoral student. “We expect our work will help form the foundation of new forms of treatment, and that these devices eventually will lead to better therapies.”

“We hope that our emerging noninvasive capsule technology will be able to put another tool in the medical kit, one with fewer side effects and better targeted efficacy,” said Professor Reza Ghodssi, whose (ECE/ISR) MEMS Sensors and Actuators Laboratory has been working on capsule development for five years. “Our work addresses only one of the promising research areas for this technology. We believe developing ingestible capsules is a frontier of research that requires an interdisciplinary team of doctors, engineers, biologists and data analysts to solve.” 

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