TPU-based antiplatelet cardiovascular prosthesis prepared using fused deposition modelling

This work describes the use of fused deposition modelling (FDM) to prepare antiplatelet thermoplastic polyurethane (TPU)-based tubular grafts. FDM 3D-printing technology is widely available and provides the ability to easily design tubular grafts on demand, enabling the customisation of vascular prosthesis dimensions. An antiplatelet drug, dipyridamole (DIP), was combined with TPU using hot-melt extrusion to prepare filaments. DIP cargos ranged between 5 and 20% (w/w). The resulting filaments were used to prepare small diameter vascular grafts using FDM. These grafts were characterised. Moreover, DIP release kinetics, antiplatelet activity and in vitro hemo- and cytocompatibility were evaluated. The results suggested that the materials could provide sustained DIP release for 30 days. Moreover, the presence of 5% DIP in the material showed a clear antiplatelet effect compared with pristine TPU. Alternatively, higher DIP loadings resulted higher surface roughness leading to higher platelet adhesion. Therefore, the biocompatibility of 5% DIP samples was tested showing that this type of materials allowed higher HUVEC cell proliferation compared to pristine TPU samples. Finally, DIP loaded TPU was combined with rifampicin-loaded TPU to prepare double-layered tubular grafts. These grafts demonstrated a clear antimicrobial activity against both Staphylococcus aureus and Escherichia coli.