Preparation and in vivo evaluation of surface heparinized small diameter tissue engineered vascular scaffolds of poly(-caprolactone) embedded with collagen suture

Herein biodegradable poly(epsilon-caprolactone) was electrospun into tubular microfibrous scaffolds and modified by the surface heparinization and wrapping of Type I collagen suture for enhancing anticoagulation activity and mechanical properties. The resulting scaffolds were featured by a double distribution of microfiber diameters ranged in 2.74 +/- 0.44 and 5.15 +/- 0.63 mu m on the outer surface with tensile strength of 1.36 +/- 0.37 MPa and Young's modulus of 8.31 +/- 1.87 MPa. The burst pressure after embedded with collagen suture was increased to 2419 +/- 121 mmHg, remarkably higher than that of the poly(epsilon-caprolactone)-only scaffolds (1500 +/- 136 mmHg) and native vessels. The scaffolds were evaluated in six rabbits for 20 weeks via a carotid artery interpositional model demonstrating a good patency. The effective cell infiltration, and rapid endothelialization and smooth muscle cell maturation were observed. There was no calcification in 20 weeks, and only one developed the aneurysm dilation after 16 weeks. It suggested that the surface heparinization is beneficial to improve the hydrophilicity and anticoagulation property of scaffolds, and embedment of collagen suture is useful to reinforce the mechanical properties and burst pressure.