![]() Įncouraged by the shape memory behavior and biocompatibility, many biomedical applications for SMP-based active devices have emerged. Upon cooling, the original modulus is nearly completely recovered and the primary form is stabilized. ![]() For SMPs that are actuated thermally, such as those in the present work, raising the temperature of the polymer above its characteristic glass transition temperature (T g) results in a decrease in the elastic modulus from that of the glassy state (~10 9 Pa) to that of an elastomer (~10 6 to 10 7 Pa) as the primary shape is recovered. Although there is wide chemical variation in these materials, they can be grouped into categories with high physical similarity based on the method of actuation, which can be achieved thermally, through photo-induced reaction, or by introduction of an external plasticizer. The basis for the shape memory effect has been previously described in detail. Shape memory polymers (SMPs) are a class of polymeric materials that can be fabricated into a primary shape, deformed into a stable secondary shape, and controllably actuated to recover the primary shape. Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated. Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. MethodsĪ laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. ![]() The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. ![]()
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