关键词: 人造血管, 增材制造, 高精度打印, 顺应性, 抗凝血

Abstract: Cardiovascular diseases pose a serious threat to human health. Vascular grafting restores blood vessel function by replacing damaged segments. Currently, autologous blood vessels are the clinical gold standard for transplantation. However, they are limited in availability and may lead to additional complications. Synthetic artificial blood vessels offer a new solution for vascular replacement. Large-diameter artificial blood vessels (≥ 6 mm) have achieved clinical success. However, small-diameter artificial blood vessels (< 6 mm) still face challenges, such as poor compliance with native vessels and high risk of thrombosis. In this study, we use a hybrid fabrication method that combines melt electrospinning (MES) and melt electrowriting (MEW). We construct a small-diameter artificial blood vessel using polycaprolactone (PCL) as the base material. We modify the vessel surface with heparin to give it anticoagulant properties. We first confirm the successful grafting of heparin using infrared spectroscopy (qualitative) and ultraviolet spectroscopy (quantitative). Then we evaluate the surface wettability, mechanical properties, cell compatibility, and anticoagulant performance. The results show that heparin modification significantly improves surface hydrophilicity. The water contact angle decreases from 125.3° to 0°. The MEW scaffold improves the mechanical strength of the vessel. Heparin modification does not negatively affect the mechanical performance. We measure compliance by cyclic tensile tests. The compliance values are 9.71±0.42, 9.62±0.35, and 9.67±0.29 %/100mmHg. These values meet the compliance requirements of various native blood vessels. CCK-8 tests show that the cell viability of heparin-functionalized vascular grafts exceeds 80%, indicating good cytocompatibility. Hemolysis tests confirm that the hemolysis rates of the heparinized grafts remain below 5%, demonstrating favorable hemocompatibility. Clotting assay results indicate that the anticoagulant performance improves with increasing heparin concentration. Notably, no visible clot formation occurs within 6 minutes on the grafts modified with 3 mg/mL heparin, confirming the effective anticoagulant properties conferred by heparin functionalization. This study successfully constructs a small-diameter composite artificial blood vessel with anticoagulant function. It provides a technical and experimental basis for the development of small-diameter vascular grafts.

Key words: artificial blood vessel, additive manufacture, high-precision printing, compliance, anticoagulation