Abstract There has been increasing interest over recent years in the application of three-dimensional (3D) printing technologies in the biomedical field. One such method is Direct Ink Writing (DIW); this approach has the potential advantage of allowing room-temperature deposition of materials, presented as an ink, to build complex architectures. DIW offers the ability to process biomaterials containing temperature-sensitive components. Due to the fabrication principles of DIW, there are specific rheological requirements that the ink must exhibit for the 3D construction. For this reason, hydrogel-based liquid feed stocks have been the focal point of ink development. As a consequence, studies based on inks comprising hydrophobic biomaterials, which are insoluble in water and hence unsuited to the hydrogel approach, have been limited. In this study, we investigate novel inks that utilize polycaprolactone (PCL), a hydrophobic polymer, as the primary constituent by dissolving the polymer in solvent systems based on dichloromethane (DCM) and acetone (ACE). Moreover, polyethylene oxide (PEO) was incorporated into the PCL systems in order to extend the range of hydrophilicity of the systems. The rheological properties of the inks were investigated as a function of polymer composition and solvent system. Woodpile constructs of PCL and PCL/PEO were fabricated using DIW method and were assessed by a series of material characterisation. The type of solvent system had a noticeable impact on the ink rheology, which ultimately affected the surface properties. The incorporation of PEO particularly enhanced the roughness and wettability of the constructs. Our results support the use of DIW as a new means to process hydrophobic polymers for biomedical applications.

中文翻译：

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基于聚己内酯/聚环氧乙烷的 3D 结构的直接墨水书写

摘要 近年来，人们对三维 (3D) 打印技术在生物医学领域的应用越来越感兴趣。一种这样的方法是直接墨水书写（DIW）；这种方法具有允许室温沉积材料（以墨水形式呈现）以构建复杂架构的潜在优势。DIW 能够处理含有温度敏感成分的生物材料。由于 DIW 的制造原理，对于 3D 结构，油墨必须表现出特定的流变要求。出于这个原因，基于水凝胶的液体原料一直是油墨开发的重点。因此，基于包含疏水生物材料的油墨的研究受到限制，该材料不溶于水，因此不适合水凝胶方法。在这项研究中，我们通过将聚合物溶解在基于二氯甲烷 (DCM) 和丙酮 (ACE) 的溶剂系统中，研究了利用疏水性聚合物聚己内酯 (PCL) 作为主要成分的新型油墨。此外，聚环氧乙烷 (PEO) 被纳入 PCL 系统以扩展系统的亲水性范围。研究了作为聚合物组成和溶剂系统函数的油墨的流变性能。PCL 和 PCL/PEO 的木桩结构是使用 DIW 方法制造的，并通过一系列材料特性进行评估。溶剂系统的类型对油墨流变性有显着影响，最终影响表面特性。PEO的掺入尤其增强了结构的粗糙度和润湿性。