4D printing of personalized shape memory polymer vascular stents with negative Poisson’s ratio structure: A preliminary study

Four-dimensional (4D) printing, integrates transformation information into three-dimensional (3D)-printed structures, which means that 3D-printed structures are able to change their shapes, properties, or functionalities over time. Here, two types of shape memory personalized vascular stents with negative Poisson’s ratio structure are developed via 4D printing. The genetic algorithm is used to optimize the structure. Axial compression tests, radial compression tests and three-point bending tests are carried out to study the mechanical properties of the stents. In addition, fluid-structure interaction and stress distribution during the shape recovery process are investigated based on finite element method. The shape memory behaviors of the stents are excellent and in vitro feasibility tests demonstrate that the stents can expand the simulated narrow blood vessel rapidly. Therefore, 4D printed shape memory stents with negative Poisson’s ratio structure are highly promising for the treatment of vascular stenosis.