Abstract：
3D bioprinting of elastic cartilage tissues that are mechanically and structurally comparable to their native counterparts, while exhibiting favorable cellular behavior, is an unmet challenge. A practical solution for this problem is the multi-material bioprinting of thermoplastic polymers and cell-laden hydrogels using multiple nozzles. However, the processing of thermoplastic polymers requires high temperatures, which can damage hydrogel-encapsulated cells. In this study, the authors developed waterborne polyurethane (WPU)-polycaprolactone (PCL) composites to allow multi-material co-printing with cell-laden gelatin methacryloyl (GelMA) hydrogels. These composites can be extruded at low temperatures (50-60 °C) and high speeds, thereby reducing heat/shear damage to the printed hydrogel-capsulated cells. Furthermore, their hydrophilic nature improved the cell behavior in vitro. More importantly, the bioprinted structures exhibited good stiffness and viscoelasticity compared to native elastic cartilage. In summary, this study demonstrated low-temperature multi-material bioprinting of WPU-PCL-based constructs with good mechanical properties, degradation time-frames, and cell viability, showcasing their potential in elastic cartilage bio-fabrication and regeneration to serve broad biomedical applications in the future.
摘要：
弹性软骨组织的三维（3D）生物打印，在机械和结构上与它们的天然对应物相当，同时表现出良好的细胞行为，是一个未满足的挑战。该问题的实际解决方案是使用多个喷嘴对热塑性聚合物和载有细胞的水凝胶进行多材料生物打印。然而,热塑性聚合物的加工需要高温，会破坏水凝胶包裹的细胞。在这项研究中,我们开发了水性聚氨酯（WPU）-聚己内酯（PCL）复合材料，以允许与载有细胞的明胶甲基丙烯酰（GelMA）水凝胶进行多材料共印刷。这些复合材料可以在低温（50-60°C）和高速下挤出，从而减少对打印的水凝胶包封的细胞的热/剪切损伤。此外，它们的亲水性质改善了体外细胞行为。更重要的是,与天然弹性软骨相比，生物打印结构表现出良好的刚度和粘弹性。总之,我们的研究证明了基于WPU-PCL的构造的低温多材料生物打印具有良好的机械性能，退化时间框架，和细胞活力，展示了它们在弹性软骨生物制造和再生方面的潜力，以在未来为广泛的生物医学应用服务。本文受版权保护。保留所有权利。
