背景:三维(3D)打印解剖模型的使用在研究中稳步增长,并作为临床决策的工具。研究了聚合物和超材料的机械性能,以评估它们在模拟主动脉血管壁生物力学中的应用。
方法:进行单轴拉伸试验以确定弹性模量,机械应力,和3D打印样品的应变。我们使用了多种材料的组合,旨在模仿生物组织的特性,刚性的VeroTM家族,和柔性Agilus30™。超材料是通过镶嵌晶胞来设计的,这些晶胞被用作晶格增强以调整其机械性能。晶格增强基于两组图案,主要响应链节/线之间的运动(链和针织)或变形(折纸和钻石晶体)。将打印材料的机械性能与健康和动脉瘤主动脉的特征进行了比较。
结果:单轴拉伸测试表明,使用格构钢筋增加了刚度,并可能增加产生的最大应力。晶格增强的图案和材料可以增加或减少最大应力下的应变,这也受到所用基础材料的影响。印刷样品显示最大应力范围为0.39±0.01MPa至0.88±0.02MPa,最大应力应变范围为70.44±0.86%至158.21±8.99%。通过在主动脉模型上插入设计为晶格增强的超材料以模拟腹主动脉瘤来创建应用的示例。
结论:打印模型获得的最大应力与文献报道的主动脉组织相似,尽管模型不能完美地再现生物组织行为。
BACKGROUND: The use of three-dimensional (3D) printed anatomic models is steadily increasing in research and as a tool for clinical decision-making. The mechanical properties of polymers and
metamaterials were investigated to evaluate their application in mimicking the biomechanics of the aortic vessel wall.
METHODS: Uniaxial tensile tests were performed to determine the elastic modulus, mechanical stress, and strain of 3D printed samples. We used a combination of materials, designed to mimic biological tissues\' properties, the rigid VeroTM family, and the flexible Agilus30™.
Metamaterials were designed by tessellating unit cells that were used as lattice-reinforcement to tune their mechanical properties. The lattice-reinforcements were based on two groups of patterns, mainly responding to the movement between links/threads (chain and knitted) or to deformation (origami and diamond crystal). The mechanical properties of the printed materials were compared with the characteristics of healthy and aneurysmal aortas.
RESULTS: Uniaxial tensile tests showed that the use of a lattice-reinforcement increased rigidity and may increase the maximum stress generated. The pattern and material of the lattice-reinforcement may increase or reduce the strain at maximum stress, which is also affected by the base material used. Printed samples showed max stress ranging from 0.39 ± 0.01 MPa to 0.88 ± 0.02 MPa, and strain at max stress ranging from 70.44 ± 0.86% to 158.21 ± 8.99%. An example of an application was created by inserting a metamaterial designed as a lattice-reinforcement on a model of the aorta to simulate an abdominal aortic aneurysm.
CONCLUSIONS: The maximum stresses obtained with the printed models were similar to those of aortic tissue reported in the literature, despite the fact that the models did not perfectly reproduce the biological tissue behavior.