Implantable Device Adheres to Muscle, Treats Atrophy

Scientists at the Wyss Institute for Biologically Inspired Engineering at Harvard have developed a mechanically active gel-elastomer-nitinol tissue adhesive, otherwise known as MAGENTA. The implantable device functions as a soft robot, and it can be adhered to the outside of a muscle. When an electrical charge is applied to the device, a spring inside made from nitinol (a shape memory alloy) heats up and begins to actuate, creating a contraction and stretching effect on the attached muscle. In an animal model of muscle atrophy, the device slowed atrophy compared with untreated muscles, suggesting that is has potential to prevent or even reverse atrophy in various conditions.

Muscle atrophy, where muscles progressively waste away, can be caused by a variety of factors, from immobility because of injury, to neurological disorders, such as amyotrophic lateral sclerosis and multiple sclerosis. One potential method to treat atrophy involves stimulating and manipulating muscles in the form of mechanotherapy. However, just massaging someone’s muscles is difficult to achieve in a controlled, sustained and consistent way. A system that can deliver even muscle contraction and stretching, and affect both superficial and deeper layers of muscle, would be highly beneficial.

This latest tech from the Harvard Wyss Institute, called MAGENTA, aims to achieve this. “With MAGENTA, we developed a new integrated multi-component system for the mechanostimulation of muscle that can be directly placed on muscle tissue to trigger key molecular pathways for growth,” said David Mooney, a researcher involved in the study. “While the study provides first proof-of-concept that externally provided stretching and contraction movements can prevent atrophy in an animal model, we think that the device’s core design can be broadly adapted to various disease settings where atrophy is a major issue.”  

The actuating spring at the heart of the MAGENTA device is shielded in an elastomer matrix to prevent the generated heat from affecting nearby tissues, and the systems also incorporates a tough adhesive that welds the device to the underlying muscle, along the natural axis of muscle movement. The researchers have also been experimenting with using a laser to heat the spring, making the system wireless.

“The growing realization that mechanotherapies can address critical unmet needs in regenerative medicine in ways that drug-based therapies simply cannot, has stimulated a new area of research that connects robotic innovations with human physiology down to the level of the molecular pathways that are transducing different mechanical stimuli,” said Donald Ingber, Wyss Founding Director. “This study by Dave Mooney and his group is a very elegant and forward-looking example of how this type of mechanotherapy could be used clinically in the future.”

The MAGENTA device with its tough hydrogel adhesive surface (shown on the left) was implanted on a mouse’s calf muscle that in the atrophy model then was immobilized for a longer period of time to induce muscle wasting. Actuating the device by turning the electricity on lets it contract, generating mechanical stimulation to the underlying muscle, whereas turning the electricity off allows the device and muscle to relax (top row on the right). The panels on the bottom right show where muscle tissue is displaced as a result of contraction and relaxation of MAGENTA with a color shift from blue to red indicating displaced areas in muscle tissue.

Study in Nature Materials: Active tissue adhesive activates mechanosensors and prevents muscle atrophy

Via: Wyss Institute