4D printed porous radiopaque shape memory polyurethane for endovascular embolization

Four-dimensional (4D) printing has great potential for fabricating patient-specific, stimuli-responsive 3D structures for the medical sector. Porous Shape memory polymers have high volumetric expansion and enhanced biological activity, which make them as ideal candidates for implant materials through minimally invasive surgical procedures. The objective of the present work is to develop a radiopaque, porous, and custom shaped shape memory polyurethane (SMPU) for its application in endovascular embolization. In this paper, the porous SMPU was fabricated by combining extrusion, fused filament fabrication (FFF) and salt leaching. The filament for FFF was produced by extruding the mixture of SMPU, NaCl, and Tungsten at the desired composition. The 3D printed and salt leached porous SMPU was observed to have the porosity in the range of 32.7-36% and pore sizes of < 250 mu m with anthe interconnected network. The porous Tungsten SMPU showed the improved radiopacity, increased storage modulus, and also, excellent shape holding and shape recovery up to 100%. The feasibility of combining fused filament fabrication and salt leaching technique was established for fabricating the radiopaque porous SMPU having the required characteristics for embolization, which can be explored by the Interventional Radiologist.