Indirect three-dimensional printing: A method for fabricating polyurethane-urea based cardiac scaffolds.

Biomaterial scaffolds are a key part of cardiac tissue engineering therapies. Our group has recently synthesised a novel polycaprolactone based polyurethane-urea copolymer that shows improved mechanical properties compared to its previously published counterparts. The aim of this study was to explore whether indirect 3D printing could provide a means to fabricate this novel, biodegradable polymer into a scaffold suitable for cardiac tissue engineering. Indirect 3D printing was carried out through printing water dissolvable poly(vinyl alcohol) porogens in three different sizes based on a wood-stack model, into which a polyurethane-urea solution was pressure injected. The porogens were removed, leading to soft polyurethane-urea scaffolds with regular tubular pores. The scaffolds were characterised for their compressive and tensile mechanical behaviour; and their degradation was monitored for 12 months under simulated physiological conditions. Their compatibility with cardiac myocytes and performance in novel cardiac engineering-related techniques, such as aggregate seeding and bi-directional perfusion, was also assessed. The scaffolds were found to have mechanical properties similar to cardiac tissue, and good biocompatibility with cardiac myocytes. Furthermore, the incorporated cells preserved their phenotype with no signs of de-differentiation. The constructs worked well in perfusion experiments, showing enhanced seeding efficiency. This article is protected by copyright. All rights reserved