Parasite-Inspired Medical Device Mimics Tapeworm Hooks for Soft Tissue Anchoring

Image: Scanning electron micrographs of the fully assembled mechanism shown in both retracted (fully armed) and deployed configurations. The hook assembly is shown in detail as well as an accompanying optical photograph of the same model, with a finger for scale.(Photo courtesy of Maquignaz et al.)

Implantable and ingestible devices offer minimally invasive approaches for drug delivery, diagnostics, and monitoring previously hard-to-detect conditions. These devices often need mechanisms to attach to tissue in order to function effectively for prolonged periods at specific locations. As a result, enhancing mechanical adhesion to particular human tissue types has become an important area of research over the last two decades, with significant implications for diagnostics, therapeutics, and surgical device design. Attachment mechanisms can help medical devices target specific regions of the gastrointestinal (GI) tract or other soft tissues for tasks such as sensing, sample collection, and drug delivery. Inspired by the attachment structures found in parasites, researchers have now developed a millimeter-scale mechanism to anchor medical devices to soft tissues.

Scientists from Harvard John A. Paulson School of Engineering and Applied Science at Harvard University (SEAS, Cambridge, MA, USA) looked to parasites for inspiration in creating methods to affix small-scale medical devices to soft tissues, such as the gastrointestinal tract, for functions like sensing, sample collection, and extended drug release. Evolution has produced a variety of biomechanical structures for tissue attachment, and the researchers chose to model their design after the curved hook arrays used by certain species of tapeworms. The device, made of stainless steel and polyimide film, features curved hooks that are automatically deployed when external force is applied to the platform.

The device, presented in a paper published in the journal PNAS Nexus, was built using laminate manufacturing techniques, where layers are bonded with adhesive. It weighs just 44 mg and measures less than 5 mm in diameter when deployed, making it small enough to be integrated into ingestible capsule robots. According to scientists, this device can be used in various medical contexts. For example, it could serve as a platform to study how different parasite attachment structures impact tissue irritation and host pathology, paving the way for the development of medical devices that minimize patient morbidities. Future research may focus on further miniaturizing the device for easier integration into surgical tools, thereby reducing tissue damage during use.