A Knitted, Fibrin-Covered Polycaprolactone Scaffold for Tissue Engineering of the Aortic Valve

Abstract

State-of-the-art tissue engineered heart valves are not strong enough to withstand aortic blood pressure levels. When a strong and slowly degrading scaffold is used, the starting position of valvular tissue engineering is a stronger valve and seeded cells are allowed more time to create a strong extracellular matrix. A polycaprolactone knitted patch with leaflets was developed as a valvular scaffold. It was sutured into a tube and covered with fibrin gel. The opening and closing behavior and leakage of knitted scaffolds without cells were studied and compared to those of stentless porcine valves. An MTT test was performed on polycaprolactone and fibrin. A loading device was developed to study the durability of the knitted scaffold. The scaffold showed proper opening and it showed coaptation upon closing, but a 39 +/- 3% (n = 3) leakage, compared to a 8 +/- 1% (n = 3) leakage of tested porcine valves. MTT tests showed that polycaprolactone and fibrin are biocompatible materials. Durability testing of the knitted scaffold (n = 1) did not show rupture after ten million loading cycles. A tissue engineering process that includes cell culture will have to show whether this scaffold, besides mechanically reliable and biocompatible, is suitable to lead to a functional, nonregurgitant, durable aortic valve.