The National Institutes of Health recently awarded a Bioengineering Research Partnership Grant for “Shape Memory Polymer Devices for Treating Stroke” which is a partnership between Lawrence Livermore National Laboratory (lead institution) and two departments at UC Davis (Immunology and Radiology).  The development and testing of two complementary devices is proposed:  a mechanical clot extraction system and a neurovascular stent.  The clot extraction system will address the current clinical need for acute ischemic stroke treatment and the stent will address the chronic problem of stenosis and/or restenosis of the neurovasculature.  Both of these devices utilize photomechanical micro-actuators based on laser-activated shape memory polymer. (SMP).

SMP is a material that will have a significant impact on clinical medicine.  SMP is a relatively new material that is similar to shape memory in its ability to actuate from an initial deformed shape into a second, pre-determined shape.  Shape memory metals are currently very popular in medicine as a material for making vascular stents.  SMP has advantages over shape memory metals for certain applications, including cost, higher recoverable strain levels, ease of manufacturing, better flexibility in navigating tortuous paths, and great versatility in fabricating extremely small, highly complex actuators.  Potential applications of SMP include stents, stent release mechanisms, embolic coil release mechanisms, thrombus extraction devices, and many others.