Making artificial bile ducts in vitro for repairing and replacing diseased bile ducts is an important concept in tissue engineering. This study printed a tubular composite scaffold using polycaprolactone (PCL) through the current 3D printing method. It served as a matrix for the organoid cells of the bile duct to proliferation, migration, and differentiation. The PCL scaffold full of bile duct-like organ cells can achieve the effect of bionics, replacing the original bile duct to perform its proper function. In order to enrich the performance of the tubular scaffold, hydrogels were also used in this study. Applying a layer of gelatin methacryloyl (GelMA) hydrogel with an appropriate thickness on the outer layer of the PCL scaffold not only protects and supports the scaffold, but also improves the biocompatibility of the printed bile duct. In addition, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles dispersed in GelMA served as the contrast agent to monitor the repair of the lesion site and the degradation of the bile duct in real time by magnetic resonance imaging (MRI). In this study, a tubular composite scaffold that could reconstruct bile duct function and possess a real-time MRI imaging property was constructed by 3D printing. After 13 days of the co-culture of bone marrow derived stem cells (BMSCs), the survival rate of the BMSCs was greater than 95%, and the coverage of the BMSCs was as high as 90%. At the same time, the compression modulus of the stent could reach 17.41 kPa and the Young's modulus could reach 5.03 kPa. Thus, the mechanical properties of it can meet the needs of human implantation. USPIO can achieve MRI imaging in situ and nondestructively monitor the degradation of the stent in the body. In summary, PCL/GelMA/USPIO bile duct scaffolds are beneficial to the proliferation of cells on the scaffolds and can be used to construct biologically active artificial bile ducts.

中文翻译：

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一种含有 USPIO 的新型 3D 打印 PCL/GelMA 支架，用于 MRI 引导的胆管修复。

在体外制造人造胆管以修复和替换患病的胆管是组织工程中的一个重要概念。本研究通过当前的 3D 打印方法使用聚己内酯 (PCL) 打印了管状复合支架。它作为胆管类器官细胞增殖、迁移和分化的基质。充满胆管样器官细胞的PCL支架可以达到仿生学的效果，替代原有的胆管发挥其应有的功能。为了丰富管状支架的性能，本研究还使用了水凝胶。在PCL支架外层涂上一层适当厚度的明胶甲基丙烯酰（GelMA）水凝胶，不仅可以保护和支撑支架，还可以提高印刷胆管的生物相容性。此外，分散在 GelMA 中的超小超顺磁性氧化铁 (USPIO) 纳米粒子作为造影剂，通过磁共振成像 (MRI) 实时监测病变部位的修复和胆管的退化。在这项研究中，通过3D打印构建了一种可以重建胆管功能并具有实时MRI成像特性的管状复合支架。骨髓源性干细胞（BMSCs）共培养13天后，BMSCs的存活率大于95%，BMSCs的覆盖率高达90%。同时，支架的压缩模量可达17.41 kPa，杨氏模量可达5.03 kPa。因此，它的力学性能可以满足人体植入的需要。USPIO可以实现原位MRI成像，无损监测支架在体内的降解情况。综上所述，PCL/GelMA/USPIO胆管支架有利于支架上细胞的增殖，可用于构建具有生物活性的人工胆管。