Daniel L. Schumann

Mechanical Properties of Mechanical Actuator for Treating Ischemic Stroke

In this paper a novel shape memory polymer (SMP) microactuator for treating ischemic stroke is introduced. This device provides a new treatment modality that could enable significant improvements in therapeutic stroke outcomes, ultimately improving mortality rates and decreasing morbidity, thereby reducing the cost of rehabilitation and improving the quality of life. Using differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) to define the thermo-mechanical behavior of SMP, we provide useful information about the polymer structure, conditions for device actuation, and an estimate of the recovery forces the device is capable of delivering during the transition between its straight and coiled shape. In addition, experimental determination of the maximum amount of pressure and force against which the microactuator coil can hold a clot is reported. The results of these tests establish that the device can successfully hold a clot against forces and pressures well above those expected in physiological systems for clot extraction, rendering it as an exciting new technology for treating ischemic stroke.

Laser-activated shape memory polymer microactuators for treating stroke

Summary form only given. We present interventional devices for treating ischemic stroke. The development and testing of two complementary devices is proposed: a mechanical clot extraction system and a neurovascular stent. These devices are laser-activated shape memory polymer microactuators.

Thin-walled compliant plastic structures for meso-scale fluidic systems

Thin-walled, compliant plastic structures for meso-scale fluidic systems were fabricated, tested and used to demonstrate valving, pumping, metering and mixing. These structures permit the isolation of actuators and sensors form the working fluid, thereby reducing chemical compatibility issues. The thin-walled, compliant plastic structures can be used in either a permanent, reusable system or as an inexpensive disposable for single-use assay systems. The implementation of valving, pumping, mixing and metering operations involve only an elastic change in the mechanical shape of various portions of the structure. Advantages provided by the thin-walled plastic structures include reduced dead volume and rapid mixing. Five different methods for fabricating the thin-walled plastic structures discussed including laser welding, molding, vacuum forming, thermal heat staking and photolithographic patterning techniques.