Photopolymerizable Elastomers for Vascular Tissue Regeneration

The aim of this study was to design new resin formulations for blood vessel substitutes with small inner diameter that can be 3D-printed by Additive Manufacturing (AM). Commercially available urethane oligomer acrylates as cross-linking agents (CAs) with different reactive diluents (RDs) and/or thiol chain transfer agents (CTAs) were examined. It could be shown that the properties of photopolymers of carefully selected CA/RD/CTA combinations can be varied in a wide range, also to fit with those of natural blood vessels. Moreover, these materials showed good biocompatibility in in-vitro cell culture tests with endothelial cells. A new method to assess the tear resistance of the new materials in comparison with natural blood vessels was designed and established. The tear resistance of the developed photopolymers already approaches those of natural material, although there is still need of improvement. The 3D-structuring of optimized resin system succeeded. Hence AM has proven to be an ideal tool to manufacture parts with the complex structure of natural blood vessels.