Non-invasive transcutaneous piezoelectric muscle stimulation

• Applicants: Professorin Dr.-Ing. Birgit Glasmacher; Dr. Doha Obed
• Subject Area: Orthopaedics, Traumatology, Reconstructive Surgery
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543397401

This research project is of interest for the rehabilitation of patients after traumatic nerve injuries in the upper and lower extremities. These primarily include traumatic amputation injuries but also injuries to the nerve plexuses and the spinal cord. After nerve fibers are severed, parts of the nerve fibers die. In addition to the loss of sensitivity in the affected areas of the body, there is also a loss and paralysis of the respective muscle function since the electrical signal can no longer be transmitted to the target location, the neuromuscular junction of the muscle. In the case of simple nerve injuries, the nerve can be repaired surgically. This possibility does not exist in the case of direct injuries to the spinal cord. In all cases, the goal is to restore nerval continuity to its target area. However, due to nerve degeneration, nerve function may not always be restored. The nerve fibers must grow back the entire distance from the trauma zone to the respective target muscle. This can take several months. During this time, many of the muscles lose their function because the electrical nerve impulse is missing. This in turn results in limited long-term functional results, which are worse the closer the injuries are to the spinal cord. The aim of the proposed project is to research a novel magnetic piezoelectric fiber fleece that allows muscle stimulation through the skin by applying an external magnetic field. To achieve the project goal, the initial focus is on producing a flexible fiber fleece made of PVDF using the electrospinning process for muscle stimulation. Optimum strength of the fiber fleece must be achieved, which facilitates implantation and promotes interaction with the muscle tissue. For a targeted deformation of the fiber fleeces, they should be functionalized, which enables deflection within a magnetic field. The deformation should then generate an electrical current of at least 20 μA, which can stimulate the muscle. To demonstrate the functionality of the fiber fleeces, cadaver models are initially used, particularly in order to reduce necessary animal testing and possible animal suffering. The muscle contractility of the euthanized animals is still present. In addition to functionality, biocompatibility is also examined. The degradation and thus long-term functionality is examined both in vitro and on explants. Based on this, the possible degradation of the implanted fiber fleeces is compared with degradation tests that took place at the same time. Finally, an in vivo animal experiment follows to demonstrate transcutaneous muscle stimulation of living muscles.

• DFG Programme: Research Grants