Research on the Microstructure Construction Technology of Fully Degraded Polymer Vascular Stent Based on Electric Field Driven 3D Printing

The so-called fourth-generation biodegradable vascular stent has become a research hotspot in the field of bio-engineering because of its good degradation ability and drug-loading characteristics. However, the preparation of polymer-degraded vascular stents is affected by known problem such as poor process flexibility, low forming accuracy, large diameter wall thickness, limited complex pore structure, weak mechanical properties of radial support and high process cost. In this study, a deposition technique based on a high-voltage electric-field-driven continuous rotating jet is proposed to fabricate fully degraded polymer vascular stents. The experimental results show that, due to the rotation of the deposition axis, the deposition direction of PCL (polycaprolactone) micro-jet is always tangent to the surface of the deposition axis. The direction of the viscous drag force is also consistent with the deposition direction of the jet. It is shown that by setting different rotation speeds of deposition axis ω and linear motion speeds of the nozzle V, the direction of rotation, pitch and angle of the individual printed spiral curve can be precisely tuned. In the process of multiple spiral curves matching the deposition forming thin wall tube mesh, the mesh shape and size of the thin wall tube can be accurately controlled by changing the number of matching spiral curves and the size of the matching position bias distance. Finally, the characteristics of a PCL tubular stent sample (with uniform-size microfibers and mesh shape), fabricated under the appropriate process parameters are described in detail.