Abstract

Synthetic vascular grafts have been widely used for arterial bypass in patients with cardiovascular disease, but progress is currently limited by thrombogenicity, lack of growth potential, biocompatibility et al. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a member of PHA family, which are linear polyesters produced in nature by bacteria. Both PHA and polylactide (PLA) show good mechanical properties and biocompatibility. A new kind of bio-synthetic vascular grafter was woven with a multi-strand fiber made from PHBV and PLA blend. Mechanical properties, biocompatibility and biodegradability of both the fiber and the tubular graft were evaluated. Furthermore, the degradation products of the graft were non-toxic and beneficial for reducing the inflammations significantly. Combined with its good biocompatibility, this PHBV/PLA woven scaffold was promising for medical applications. Each PHBV/PLA fiber consisted of 72 strands and the diameter of each is about 14 µm. The fiber was evaluated to of high tensile strength, good elasticity and biocompatibility. When used as medical suture, fibrous capsule could be avoided and the scar size could be reduced. Woven by the fiber, the graft has an internal diameter ranged from 3 to 10 mm. In vitro experiments proved that the endothelial cells could adhere and grow well on the scaffold. We further implanted the graft into miniature pigs and it showed great suture ability during the operation and bio-compatibility after implantation. What’s more, the graft maintained its patency in vivo for more than 3 months. The compatibility and mechanical properties could be further improved with further modification of the graft. The results proved that a screwed thread shape showed better performance. Certain miRNAs were also introduced to facilitate the graft by regulating the vascular wall cells and promoting vascularization. By planting seed cells onto the graft, the tissue engineered vascular graft became promising for future medical applications.