Small Diameter Vascular Grafts Made in Minutes

This study developed a rapid additive-manufacturing approach for customizable small-diameter vascular grafts using focused rotary jet spinning (FRJS). Poly(L-lactide-co-ε-caprolactone) (PLCL) nanofibers were deposited onto interchangeable mandrels, enabling control over graft diameter, length, wall thickness, curvature, branching geometry, fiber diameter, and fiber alignment. Grafts ranging from 0.5 to 10 mm inner diameter were fabricated within minutes, with 0.5 mm grafts produced and removed from the mandrel in approximately 90 seconds. Mechanical characterization showed that circumferentially aligned grafts tolerated an average internal pressure of approximately 276 mmHg before fluid leakage, while bifurcated grafts reached approximately 160 mmHg at their junctions. Suture retention strength averaged approximately 2.25 N for the vascular grafts compared with approximately 0.75 N for native rat femoral arteries. Tensile testing of flat fiber scaffolds demonstrated anisotropic mechanics, with Young’s moduli of approximately 1.8 MPa circumferentially and 0.75 MPa longitudinally. Hydrated cyclic testing showed that 0.5 mm PLCL vascular grafts had an average tensile modulus of 910 kPa compared with 623 kPa for native rat femoral arteries, making the grafts approximately 46% stiffer while retaining consistent behavior through repeated loading. The grafts also supported endothelial cell coverage, smooth muscle cell infiltration, and collagen deposition in vitro. In rat femoral artery and vein replacement models, the cell-free grafts maintained blood flow, oxygen saturation, and tissue perfusion for up to four weeks without observed thrombosis or loss of patency, while showing cellular infiltration, endothelialization, smooth muscle organization, and early extracellular matrix remodeling. Overall, the study demonstrates that FRJS can rapidly fabricate mechanically functional and customizable nanofibrous vascular grafts with potential for point-of-care or intraoperative production.