Biomimetic Vascular Scaffold with Seamless Electrospun Aligned Nanofiber Conduit and 3D-Printed Coil Reinforcement

Although the clinical need for bioengineered blood vessels is growing, options for vascular conduits are currently limited. The aim of this study is to develop a novel scaffold fabrication method for use as a small-diameter vascular graft and to evaluate its biocompatibility, cell attachment, and mechanical properties. This scaffold consists of a tubular polycaprolactone parallel nanofiber section (a seamless tube of fibers aligned along the long axis) reinforced with 4-axis 3D printed spiral polycaprolactone. The final structure was coated with collagen and cultured with various cells. High-resolution field emission-scanning electron microscopy images confirm the successful fabrication of seamless parallel fibrous tubes (as small as 300 µm) and fusion of the fibers to the spiral reinforcement. Biocompatibility assays on the scaffold indicate no cell toxicity, and the parallel fibers successfully oriented the cells cultured inside the tube, thereby mimicking their natural orientation in vascular tissue. The spiral reinforcement was successfully attached to the inner tube, which significantly improved the tube's mechanical strength compared to the non-reinforced groups. These results suggest that this new fabrication method of polycaprolactone/collagen parallel tubular nanofibers reinforced by using 4-axis 3D printing techniques could play a promising role in future bioengineered vascular tissues or other tubular tissues.