Three-dimensional (3D) printing provides a new approach of fabricating implantable products because it permits a flexible manner to extrude complex and customized shapes of the tissue scaffolds. Compared with other printable biomaterials, the polyurethane elastomer has several merits, including excellent mechanical properties and good biocompatibility. However, some intrinsic behavior, especially its high melting point and slow rate of degradation, hampered its application in 3D printed tissue engineering. Herein, we developed a 3D printable amino acid modified biodegradable waterborne polyurethane (WBPU) using a water-based green chemistry process. The flexibility of this material endows better compliance with tissue during implantation and prevents high modulus transplants from scratching surrounding tissues. The histocompatibility experiments show that the WBPU induces no apparent acute rejection or inflammation in vivo. We successfully fabricated a highly flexible WBPU scaffold by deposition 3D printing technology at a low temperature (50°C ~ 70 °C), and the printed products could support the adhesion and proliferation of chondrocytes and fibroblasts. The printed blocks possessed controllable degradability due to the different amounts of hydrophilic chain extender and did not cause accumulation of acidic products. In addition, we demonstrated that our WBPU is highly applicable for implantable tissue engineering because there is no cytotoxicity during its degradation. Taken together, we envision that this printable WBPU can be used as an alternative biomaterial for tissue engineering with low temperature printing, biodegradability, and compatibility.

中文翻译：

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具有可生物降解性和高柔韧性的新型水性聚氨酯，可用于3D打印。

三维（3D）打印提供了一种制造可植入产品的新方法，因为它允许灵活地挤出组织支架的复杂且自定义形状。与其他可印刷生物材料相比，聚氨酯弹性体具有许多优点，包括优异的机械性能和良好的生物相容性。但是，某些固有行为，特别是其高熔点和缓慢的降解速度，阻碍了其在3D打印组织工程中的应用。本文中，我们使用水基绿色化学工艺开发了3D可打印氨基酸改性的生物可降解水性聚氨酯（WBPU）。这种材料的柔韧性赋予了植入过程中更好的组织顺应性，并防止了高模量的移植物刮擦周围的组织。组织相容性实验表明，WBPU在体内不会引起明显的急性排斥或炎症。我们通过在低温（50°C〜70°C）下通过沉积3D打印技术成功地制造了高度柔性的WBPU支架，并且该打印产品可以支持软骨细胞和成纤维细胞的粘附和增殖。印刷的嵌段由于亲水链增长剂的量不同而具有可控制的降解性，并且不会引起酸性产物的积累。此外，我们证明了我们的WBPU非常适用于可植入组织工程，因为其降解过程中没有细胞毒性。两者合计，我们设想这种可打印的WBPU可以用作组织工程的替代生物材料，具有低温打印，可生物降解性和兼容性。