verbatim) The objective of the Bioengineering Research Partnership program is to refine materials and establish methods for application of electroactive polymers in prosthetics and interventional medical devices. Electroactive materials are materials that change shape when exposed to an electric field. They are attractive as actuators because of their high energy density - the amount of energy that can be imparted to a load for a given volume or mass of active material. Electroactive materials, chiefly the piezoceramics, have found important uses in a variety of industrial, consumer and military systems, as well as in ultrasonic transducers for medical imaging, flow measurement and therapy. The piezoceramics have not been successfully applied, however, as actuators in other medical devices. A new class of electroactive polymers has recently been discovered, which make possible the development of devices using forms that would not have been practical using available materials. These materials remain flexible, can readily be formed into a variety of shapes, and provide much larger shape changes than do previously available materials. This will make possible the development of devices using forms that would not previously have been practical. Two target application areas have been chosen: (1) next-generation prosthetic blood pumps for treatment of end-stage heart disease, and (2) advanced instrumentation for minimally invasive surgery, particularly for use in confined spaces such as the thorax. These disparate applications share the need for very compact, efficient and uncomplicated means of actuation. Both suffer today from the need for bulky actuation mechanisms that must remain physically distinct from the parts which pump blood or manipulate tissue. The technology to be developed under this program will blur the lines between structure and actuator, leading to modes of therapy that are not currently available. The Materials Research partner will work to optimize electroactive polymers, which have been developed thus far for military applications, for use in the target medical devices, and develop methods for fabrication of the required multilaminate actuator materials. As these materials are fundamentally different from active materials of actuating mechanisms used by engineers in the past, the Mechanical Engineering partner will work to develop new design methodologies for use with the new materials. The Bioengineering partner will develop prototype devices to demonstrate the potential of the technology and lay the ground work for full development of new devices. Device development is staged so that simpler, proof-of-concept designs are built in the first two years, as optimized materials and more sophisticated design tools are being developed. By year five, devices will demonstrate the full promise of the technology.
