Native tissues feature unique hierarchical designs, in which fiber units are arranged from the bottom up in anisotropic patterns. The processing of biomaterials into fibers, followed by their textile‐like assembly into complex patterns, is therefore a promising avenue to engineer native‐like tissue replacements. Here it is shown for the first time the fabrication of meter‐long hydrogel fibers prepared from engineered elastin using a microinjection system and exploiting the catalyst‐free click chemistry. Given their similarity to native elastin, the fabricated elastin‐like fibers achieved excellent stretching (500%) and recoiling performance. Moreover, the fabrication scheme is compatible with the implementation of a salt‐leaching gas‐foaming approach, resulting in highly porous elastin‐like fibers (the first of their kind). From the translation perspective, the fibers can be autoclaved, which allows for sterilization and long‐term storage. Human umbilical vein endothelial cells cultured on autoclaved fibers produced a confluent endothelial layer lining the fiber surface, in which the cells became aligned in response to physiological fiber stretching. It is also shown that these functional fibers can be assembled by weaving, braiding and knitting, with various spatial patterns. Overall, the elastin‐like fibers can be used as building blocks for the reconstruction of functional tissues using the principles of textile technology.

Research purpose: The low patency rate (less than 50% at a 5-years follow-up) of commercial vascular grafts is strongly associated with compliance mismatch between graft und native artery. To address this deficit, we investigated the influence of the material and structural elasticity on the compliance behavior of small caliber vascular graft gaining for a stress-strain behavior adapted to the native vessel. Material & Methods: By combining different thermoplastic polycarbonate urethanes (TPU) fibers with different elasticity and non-elastic polyvinylidene fluoride (PVDF) fibers in different warp knitted tubular textile structures, we incorporate material and structural elasticity in a vascular graft (I.D. < 6 mm). The evaluation of the tubular fabrics is performed by determining the compliance properties in a mean pressure range between 20 and 120 mmHg by tensile testing. Results: We identified the draw ration of the TPU fiber production, the stitch course density of the fabric and the thread tension of the TPU yarn during the warp knitting process as statistically highly significant effects ( p < .005) on the compliance. With an adapted setting of those parameters, we were able to improve the compliance of the textile vascular grafts over the entire physiological pressure range (20–120 mmHg) by 400–630 % compared to current clinical ePTFE (expanded polytetrafluoroethylene) grafts towards native vessels. Conclusion: By combining material and structural elasticity in a warp knitted textile structure, we were able to biomimic the compliance towards physiological properties. Our approach can be seen as blueprint to adapt elasticity properties in other implant applications.

In tissue engineering, electrospinning has gained significant interest due to its highly porous structure with an excellent surface area to volume ratio and fiber diameters that can mimic the structure of the extracellular matrix. Bioactive substances such as growth factors and drugs are easily integrated. In many applications, there is an important need for small tubular structures (I.D. < 1 mm). However, fabricating sub-millimeter structures is challenging as it reduces the collector area and increases the disturbing factors, leading to significant fiber loss. This study aims to establish a reliable and reproducible electrospinning process for sub-millimeter tubular structures with minimized material loss. Influencing factors were analyzed, and disturbance factors were removed before optimizing control variables through the design-of-experiments method. Structural and morphological characterization was performed, including the yield, thickness, and fiber arrangement of the scaffold. We evaluated the electrospinning process to enhance the manufacturing efficiency and reduce material loss. The results indicated that adjusting the voltage settings and polarity significantly increased the fiber yield from 8% to 94%. Variations in the process parameters also affected the scaffold thickness and homogeneity. The results demonstrate the complex relationship between the process parameters and provide valuable insights for optimizing electrospinning, particularly for the cost-effective and reproducible production of small tubular diameters.

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 (150 µ m 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.