Developed initially at Lawrence Livermore National Laboratory, and later at Texas A&M University, the use of shape memory polymer (SMP) medical devices is a new approach to embolization therapies. 

Porous SMPs are formulated to have “memory” properties, allowing them to transition between pre-set shapes under different temperatures and aqueous environments. 

SMP is constructed in an expanded shape, then compressed into a secondary shape to allow for catheter delivery to a treatment site.

Once delivered into a blood vessel, the SMP recovers its original expanded shape, which blocks blood flow in the vessel.

SMPs are based on a low-density polyurethane, and the formulation and pore sizes can be easily modified to create materials with a wide range of different properties.