Materials for the Six Million Dollar Man

Materials for the Six Million Dollar Man

SY5Y neural cells (actin--green, nuclei--blue) grown on a patterned surface of PEDOT, an electrically conducting polymer. Image obtained by Matt Meier (undergraduate in BME) and Dr. Sarah Richardson-Burns (Post-doctoral Scientist in MSE). Click to enlarge

In the future, it is possible to envision engineered devices that are seamlessly integrated into living systems. There are many examples of this from science fiction and popular culture, including artificial bionic limbs, eyes, and ears. Consider movies such as "Star Wars", and television programs such as "The Six Million Dollar Man & Bionic Woman". However, in order to make this happen, there need to be materials available that can better accommodate the dramatic differences in properties between living (biotic) systems and the synthetic (abiotic) devices.
Prof. David C. Martin and several of his colleagues at the University of Michigan have recently been given an opportunity to explore this scientific frontier in more detail through a Multi-Disciplinary University Research Initiative (MURI) award from the Army Research Office. This grant will focus on the design and development of materials at the interface between a prosthetic limb and living tissue. Four engineered materials--tissue interfaces are of interest for the project: (1) structural frame--bone, (2) wire--neurons, (3) sensor/actuator--muscle, and (4) protective coating--skin. In each case there is a need to optimize the geometry, mechanical properties, electrical properties, and regenerative capability of the interface. The goal of the five year, $5.6M project is to create the fundamental enabling technology needed to realize new generations of artificial arms and legs. It is also expected that aspects of the technologies and ideas that are developed in this research effort will have implications for other biomedical devices.
Of particular interest to the current project are soft, electrically conducting polymers that can be used to improve the long-term performance of biomedical devices when implanted in neural tissue. These materials have been of interest to Professor Martin and his students for the past several years, with a focus on improving the performance of microfabricated neural prosthetics that have been developed at the University of Michigan in the Center for Neural Communications Technology. Participating with Prof. Martin on the MURI are Profs. Daryl R. Kipke from Biomedical Engineering, Paul S. Cederna from Surgery, and Steven A. Goldstein from Orthopaedics.