Institute of Biomedical Engineering, University of Stuttgart, Stuttgart, Germany.
Faculty of Natural and Environmental Sciences, University of Kaiserslautern-Landau, Landau, Germany.
Sci Rep. 2024 Jul 15;14(1):16301. doi: 10.1038/s41598-024-66777-5.
In vitro vascular models, primarily made of silicone, have been utilized for decades for studying hemodynamics and supporting the development of implants for catheter-based treatments of diseases such as stenoses and aneurysms. Hydrogels have emerged as prominent materials in tissue-engineering applications, offering distinct advantages over silicone models for fabricating vascular models owing to their viscoelasticity, low friction, and tunable mechanical properties. Our study evaluated the feasibility of fabricating thin-wall, anatomical vessel models made of polyvinyl alcohol hydrogel (PVA-H) based on a patient-specific carotid artery bifurcation using a combination of 3D printing and molding technologies. The model's geometry, elastic modulus, volumetric compliance, and diameter distensibility were characterized experimentally and numerically simulated. Moreover, a comparison with silicone models with the same anatomy was performed. A PVA-H vessel model was integrated into a mock circulatory loop for a preliminary ultrasound-based assessment of fluid dynamics. The vascular model's geometry was successfully replicated, and the elastic moduli amounted to 0.31 ± 0.007 MPa and 0.29 ± 0.007 MPa for PVA-H and silicone, respectively. Both materials exhibited nearly identical volumetric compliance (0.346 and 0.342% mmHg), which was higher compared to numerical simulation (0.248 and 0.290% mmHg). The diameter distensibility ranged from 0.09 to 0.20% mmHg in the experiments and between 0.10 and 0.18% mmHg in the numerical model at different positions along the vessel model, highlighting the influence of vessel geometry on local deformation. In conclusion, our study presents a method and provides insights into the manufacturing and mechanical characterization of hydrogel-based thin-wall vessel models, potentially allowing for a combination of fluid dynamics and tissue engineering studies in future cardio- and neurovascular research.
体外血管模型主要由硅树脂制成，已被用于研究血液动力学和支持基于导管的疾病（如狭窄和动脉瘤）植入物的开发数十年。水凝胶已成为组织工程应用中的突出材料，由于其粘弹性、低摩擦和可调节的机械性能，相对于硅树脂模型在制造血管模型方面具有明显优势。我们的研究评估了使用 3D 打印和成型技术组合，基于特定患者的颈动脉分叉，制造由聚乙烯醇水凝胶（PVA-H）制成的薄壁解剖血管模型的可行性。模型的几何形状、弹性模量、体积顺应性和直径可扩展性通过实验和数值模拟进行了表征。此外，还与具有相同解剖结构的硅树脂模型进行了比较。将 PVA-H 血管模型集成到模拟循环回路中，初步进行基于超声的流体动力学评估。血管模型的几何形状成功复制，弹性模量分别为 0.31 ± 0.007 MPa 和 0.29 ± 0.007 MPa，适用于 PVA-H 和硅树脂。两种材料的体积顺应性几乎相同（0.346 和 0.342%mmHg），高于数值模拟（0.248 和 0.290%mmHg）。在实验中，直径可扩展性在血管模型的不同位置从 0.09 到 0.20%mmHg 不等，在数值模型中从 0.10 到 0.18%mmHg 不等，突出了血管几何形状对局部变形的影响。总之，我们的研究提出了一种方法，并提供了关于制造和机械表征基于水凝胶的薄壁血管模型的见解，这可能允许在未来的心脏和神经血管研究中结合流体动力学和组织工程研究。
