Evaluation of 3D-Printed Thermoplastic Polyurethane Nerve Guidance Conduits

Fused deposition modeling (FDM) is an emerging trend for producing nerve guidance conduits (NGCs). This technique allows distinct designs and dimensions to mimic peripheral nerve architecture and promote nerve regeneration. In this study, commercially available TPU 90A and 95A filaments were used for the fabrication of hollow simple wall (non-porous), grooved and gyroid multichannel conduits. The segmented polyurethanes were identified as PBA-MDI-BO-based polyurethanes by ¹H NMR, FTIR and Raman spectroscopy. Thermal analyses, such as DSC and TGA, demonstrated that both TPUs possess sufficient thermal stability to be processed safely under the printing conditions employed. Tensile mechanical tests accounted for their differences in hard segment content in agreement with the Shore A hardness. The measured elastic modulus, in particular, was within a range that may be advantageous for peripheral nerve repair. The gyroid multichannel design showed enhanced resistance to radial compression and highly interconnected internal structure that supported primary neural cell viability and preserved cellular functionality. Therefore, polyurethane-based nerve guidance conduits can be manufactured by FDM, rendering high printability, favorable mechanical performance without compromising biocompatibility.