UMEC, Institute of Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias 378, 4200-465 Porto, Portugal.
J Mech Behav Biomed Mater. 2011 Apr;4(3):451-60. doi: 10.1016/j.jmbbm.2010.12.006. Epub 2010 Dec 21.
The aliphatic polyesters are widely used in biomedical applications since they are susceptible to hydrolytic and/or enzymatic chain cleavage, leading to α-hydroxyacids, generally metabolized in the human body. This is particularly useful for many biomedical applications, especially, for temporary mechanical supports in regenerative medical devices. Ideally, the degradation should be compatible with the tissue recovering. In this work, the evolution of mechanical properties during degradation is discussed based on experimental data. The decrease of tensile strength of PLA-PCL fibers follows the same trend as the decrease of molecular weight, and so it can also be modeled using a first order equation. For each degradation stage, hyperelastic models such as Neo-Hookean, Mooney-Rivlin and second reduced order, allow a reasonable approximation of the material behavior. Based on this knowledge, constitutive models that describe the mechanical behavior during degradation are proposed and experimentally validated. The proposed theoretical models and methods may be adapted and used in other biodegradable materials, and can be considered fundamental tools in the design of regenerative medical devices where strain energy is an important requirement, such as, for example, ligaments, cartilage and stents.
脂肪族聚酯由于易于发生水解和/或酶促链断裂，导致生成 α-羟基酸，而这些酸通常在人体内被代谢，因此它们在生物医学应用中被广泛应用。这对于许多生物医学应用特别有用，尤其是在再生医学装置中的临时机械支撑。理想情况下，降解应与组织恢复相兼容。在这项工作中，基于实验数据讨论了降解过程中机械性能的演变。PLA-PCL 纤维的拉伸强度下降与分子量的下降遵循相同的趋势，因此也可以使用一阶方程对其进行建模。对于每个降解阶段，超弹性模型（如 Neo-Hookean、Mooney-Rivlin 和二阶简化模型）可以合理地近似材料的行为。基于这些知识，提出了描述降解过程中机械行为的本构模型，并进行了实验验证。所提出的理论模型和方法可以适应并用于其他可生物降解材料，并且可以被认为是应变能是重要要求的再生医学装置设计中的基本工具，例如，例如韧带、软骨和支架。
