Thomas Joanna, Patel Sagar, Troop Leia, Guru Robyn, Faist Nicholas, Bellott Brian J, Esterlen Bethany A
Biomedical Engineering Department, Mercer University, Macon, GA 31207, USA.
Chemistry Department, Western Illinois University, Macomb, IL 61455, USA.
Materials (Basel). 2020 Oct 27;13(21):4788. doi: 10.3390/ma13214788.
Several inflammatory conditions of the bile ducts cause strictures that prevent the drainage of bile into the gastrointestinal tract. Non-pharmacological treatments to re-establish bile flow include plastic or self-expanding metal stents (SEMs) that are inserted in the bile ducts during endoscopic retrograde cholangiopancreatography (ERCP) procedures. The focus of this study was to 3D print an anatomically accurate model of the extrahepatic bile ducts (EHBDs) with tissue-like mechanical properties to improve in vitro testing of stent prototypes. Following generation of an EHBD model via computer aided design (CAD), we tested the ability of Formlabs SLA 3D printers to precisely print the model with polymers selected based on the desired mechanical properties. We found the printers were reliable in printing the dimensionally accurate EHBD model with candidate polymers. Next, we evaluated the mechanical properties of Formlabs Elastic (FE), Flexible (FF), and Durable (FD) resins pre- and post-exposure to water, saline, or bile acid solution at 37 °C for up to one week. FE possessed the most bile duct-like mechanical properties based on its elastic moduli, percent elongations at break, and changes in mass under all liquid exposure conditions. EHBD models printed in FE sustained no functional damage during biliary stent deployment or when tube connectors were inserted, and provided a high level of visualization of deployed stents. These results demonstrate that our 3D printed EHBD model facilitates more realistic pre-clinical in vitro testing of biliary stent prototypes.
几种胆管炎症性疾病会导致胆管狭窄，从而阻碍胆汁排入胃肠道。恢复胆汁流动的非药物治疗方法包括在内镜逆行胰胆管造影（ERCP）手术期间插入胆管的塑料或自膨胀金属支架（SEM）。本研究的重点是3D打印具有组织样力学性能的肝外胆管（EHBD）解剖学精确模型，以改进支架原型的体外测试。通过计算机辅助设计（CAD）生成EHBD模型后，我们测试了Formlabs SLA 3D打印机使用根据所需力学性能选择的聚合物精确打印该模型的能力。我们发现这些打印机能够可靠地使用候选聚合物打印尺寸精确的EHBD模型。接下来，我们评估了Formlabs弹性（FE）、柔性（FF）和耐用（FD）树脂在37°C下暴露于水、盐水或胆汁酸溶液中长达一周前后的力学性能。基于其弹性模量、断裂伸长率以及在所有液体暴露条件下的质量变化，FE具有最类似胆管的力学性能。用FE打印的EHBD模型在胆管支架部署期间或插入管接头时没有受到功能损伤，并能高度清晰地显示部署的支架。这些结果表明，我们的3D打印EHBD模型有助于对胆管支架原型进行更逼真的临床前体外测试。
