Fiber-reinforced printing (FiRePrint)-a novel method for the production of load-oriented 3D scaffolds in biohybrid...

Personalized medicine focuses on the needs of individual patients and includes the use of biohybrid implants. Various textile or additively manufactured structures have been designed as load-orientated scaffolds, but they all have specific limitations. The aim of this study was to develop a new process known as fiber-reinforced printing (FiRePrint) for the fabrication of load-oriented 3D scaffolds for biohybrid implants. The FiRePrint process is intended to combine the specific advantages of textiles (high tensile strength and flexibility in a thin material) and 3D printing (ability to produce complex 3D structures). A fused deposition modeling printer was modified to facilitate continuous textile fiber feeding to the print head. This allowed the production of composite structures comprising a thermoplastic polyurethane (TPU) matrix and continuous fiber reinforcement using a polyethylene terephthalate multi-filament yarn. We also examined the mechanical properties, microscopic morphology and cell biology of the resulting scaffolds. We were able to print thin-walled (150µm layer height) scaffold structures with the flexibility of TPU and the Young's modulus and tensile strength of a textile. We were also able to print single tracks, open-porous and closed surfaces, and complex load-oriented structures (2D and 3D). The scaffold structures showed no cytotoxicity and supported cell viability, adhesion, proliferation and confluence. By combining the design flexibility of 3D printing with the mechanical properties of continuous textile fibers, we were able to fabricate load-oriented scaffolds for biohybrid implants without the current limitations of classic fabrication strategies. Our novel manufacturing technology can be used to produce biomedical scaffold structures with enhanced biomimetic mechanical properties.