BME Seminar Series: Patrick T. Mather, Ph.D.
Shape Memory Polymers: A World of Opportunities in Healthcare
Director/Syracuse Biomaterials Institute, Milton and Ann Stevenson Professor of Biomedical and Chemical Engineering, Syracuse University
Many crosslinked polymers exhibit a shape memory effect wherein a permanent shape can be prescribed during crosslinking and arbitrary temporary shapes may be set through network chain immobilization. An external stimulus, such as heat or hydration, can then trigger a return to the equilibrium shape that, in doing so, can serve some function. Indeed, such shape memory polymers (SMPs) have great potential for use in medical devices, soft actuators, and even sporting equipment. This talk will begin with some background on SMP fundamentals and then branch into two areas relevant to bioengineering and healthcare. The first area will concern our very recent research concerning shape memory induced wrinkle formation on polymeric surfaces. A transformation from smooth to wrinkled surfaces at physiological temperatures has been observed to have a dramatic effect on the behavior of adherent cells. Indeed, we find that cells orientate on actively wrinkling surfaces and they do so as a dynamic effect related to mechanisms of motility on topologically complex surfaces. The second area will concern the development of new shape memory polymers for small diameter vascular grafts. Previously we reported on a new approach to elastomeric shape memory polymers prepared using a composite design. There, we achieved the combination of shape memory and shape fixing through interpenetrating phases of elastomer matrix and semicrystalline microfibers, respectively. Here, I will present results on incorporated drugs into the composite for controlled release needed in cardiovascular applications. The rate-limiting step for drug release is water permeation through the elastomer, water playing a key role in reacting with a drug-releasing donor molecule. In this presentation, materials design, drug synthesis, composite processing, and application-specific testing will be discussed.