Fabrication of a bilayer scaffold for small diameter vascular applications.

One of the greatest challenges plaguing cardiovascular tissue engineering has been the development of a compliant vascular graft. In this work, we report the development of a synthetic vascular graft with compliance similar to native arteries at physiological pressures. A bilayer scaffold was fabricated from a solid polymeric lumen made from poly(1,8 octanediol-co-citrate) (POC) and a microfibrous medial layer composed of type I collagen, elastin, and POC. Mechanical analysis revealed dynamic compliance, ~6.9% within 1% of native vessels, 5.9%. The burst pressure was an order of magnitude lower than native vessels (~400 mmHg vs. ~3000 mmHg) but was above physiological pressure ranges. Biocompatibility studies indicated the scaffold posed no acute cytotoxic risk to relevant cell types and supported the proliferation of vascular smooth muscle cells. In addition, upon exposure of the scaffold to whole blood, there was no statistically significant hemolysis, <2%. Overall this is a promising material system and scaffold to develop a biodegradable tissue-engineered vascular graft.