Reconstructive surgery aims to restore tissue defects by replacing them with similar autologous tissue to achieve good clinical outcomes. However, often the defect is too large or the tissue available is limited, requiring synthetic materials to restore the anatomical shape and partial function. The utilization of three-dimensional (3D) printing allows for the manufacture of implants with complex geometries and internal architecture that more closely matches the required clinical needs. Synthetic polymers offer certain advantages over natural polymers as biomedical materials due to their ability to more closely mimic the mechanical and chemical properties of the native tissue. Synthetic polymer materials such as poly(lactic acid) and acrylonitrile butadiene styrene are easily 3D printed to generate 3D objects due to their flexibility in their chemical and mechanical properties and physical form. Polyurethanes (PUs) are widely used as short- and long-term, implantable medical devices due to their good mechanical properties, biocompatibility, and hemocompatibility. This article provides an overview on the advancement of 3D printable PU-based materials for biomedical applications. A summary of the chemical structure and synthesis of PUs is provided to explain how PUs may be processed into medical devices using additive manufacturing techniques. Currently, PUs are being explored by several 3D printing approaches, including fused filament fabrication, bioplotting, and stereolithography, to fabricate complex implants with precise patterns and shapes with fine resolution. PU scaffolds using 3D printing have shown good cell viability and tissue integration in vivo. The important limitations of PU printing are identified to stimulate future research. PUs offer a biocompatible, synthetic polymeric material that can be 3D printed to manufacture implants that are tailored to meet specific anatomical, mechanical, and biological requirements for biomedical applications.

中文翻译：

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生物医学应用聚氨酯三维打印的当前多功能性。

重建外科手术旨在通过用相似的自体组织替代组织缺陷来恢复组织缺陷，以达到良好的临床效果。但是，缺陷通常太大或可用组织有限，需要合成材料来恢复解剖形状和部分功能。三维（3D）打印的利用可以制造具有更复杂的几何形状和内部结构的植入物，从而更符合所需的临床需求。合成聚合物比天然聚合物作为生物医学材料具有某些优势，因为它们能够更紧密地模仿天然组织的机械和化学特性。合成聚合物材料（例如聚（乳酸）和丙烯腈丁二烯苯乙烯）易于3D打印以产生3D对象，这是因为它们在化学和机械特性以及物理形式方面具有灵活性。聚氨酯（PU）具有良好的机械性能，生物相容性和血液相容性，因此被广泛用作短期和长期的可植入医疗设备。本文概述了用于生物医学应用的3D可打印PU基材料的发展。提供了PU的化学结构和合成的摘要，以解释如何使用增材制造技术将PU加工成医疗设备。目前，PU已通过几种3D打印方法进行了探索，包括熔丝制造，生物绘图和立体光刻，制造具有精确图案和形状且具有高分辨率的复杂植入物。使用3D打印的PU支架显示出良好的细胞活力和组织整合体内。确定了PU印刷的重要局限性以刺激未来的研究。PU提供了一种生物相容的合成聚合物材料，可以对其进行3D打印以制造植入物，这些植入物可以满足生物医学应用中特定的解剖，机械和生物学要求。