Science & History: Research



Dr. Dennis’s research spans close to 20 years. His primary body of work has been involved in tissue engineering and regeneration as well as stimulation of tissues for regeneration, repair and recovery. It is this research that led him to develop a less invasive signal, that is, a pulsed electro-magnetic field (PEMF) signal. In this research he discovered that a trapezoidal wave is the optimal way for producing this type of tissue stimulation. The original intent was to develop a square wave signal, but from an engineering perspective this is almost impossible. All square wave signals essentially are trapezoidal to a great degree. Dr. Dennis’s broad research background also helped him to determine the best frequencies to be used, not only for the NASA study and device development, but also since that time and enhancing the stimulation protocols in the SomaPulse® PEMF system.

Generally, his research is in the area of tissue engineering. He also has a significant interest in robotics, modern manufacturing technologies, prosthetics, and bio-hybrid systems. This summary is somewhat technical but is typical for the complexities of bioengineering research.

Skeletal Muscle (myooids, U.S. Patent No. 6,207,451) This was the first tissue system developed in Dr. Dennis’s laboratory at the University of Michigan, and is the basis for further work in the area of engineered, self-organizing tissue systems in vitro. These skeletal muscle constructs are electrically excitable and generate measurable contractile force when stimulated. They have made excellent progress on several of these critical tissue interface technologies: nerve-muscle co-cultures and muscle-tendon junctions. They were, for example, the first to demonstrate the development of a functional nerve-muscle junction in culture, capable of sustaining the transmission of peripheral axonal action potentials to elicit active synchronized contractions in an engineered muscle. The resulting manuscript is in the final stages of review before submission at the time of this writing.

Bioreactors Dr. Dennis’s most significant supporting technology development is a bioreactor system (U.S. Patent Nos. 6,114,164 and 6,303,286). He has also developed and published the designs for electrical stimulator units, specifically designed for use with musculoskeletal tissue, and optical force transducers and other sensors for use in the bioreactor systems.

The potential applications of this research are very far reaching, and include: in vitro tissue models for research in developmental biology aging, injury, and gene therapy; engineered tissue for surgical repair; hybrid robotics, prosthetics, and biomechatronic devices.