Millon L E, Mohammadi H, Wan W K
Graduate Program in Biomedical Engineering, University of Western Ontario, London, Ontario, Canada.
J Biomed Mater Res B Appl Biomater. 2006 Nov;79(2):305-11. doi: 10.1002/jbm.b.30543.
Polyvinyl alcohol (PVA) is a hydrophilic polymer with various characteristics desired for biomedical applications and can be transformed into a solid hydrogel by physical crosslinking, using a low-temperature thermal cycling process. As with most polymeric materials, the mechanical properties of the resultant PVA are isotropic, as oppose to most soft tissues, which are anisotropic. The objective of this research is to develop a PVA-based hydrogel that not only mimics the nonlinear mechanical properties displayed by cardiovascular tissues, but also their anisotropic behavior. By applying a controlled strain to the PVA samples, while undergoing low-temperature thermal cycling, we were able to create oriented mechanical properties in PVA hydrogels. The oriented stress-strain properties of porcine aorta were matched simultaneously by a PVA hydrogel prepared (10% PVA, cycle 3, 75% initial strain). This novel technique allows the controlled introduction of anisotropy to PVA hydrogel, and gives a broad range of control of its mechanical properties, for specific medical device applications.
聚乙烯醇（PVA）是一种亲水性聚合物，具有生物医学应用所需的各种特性，并且可以通过物理交联，采用低温热循环工艺转化为固体水凝胶。与大多数聚合材料一样，所得PVA的机械性能是各向同性的，这与大多数软组织的各向异性相反。本研究的目的是开发一种基于PVA的水凝胶，它不仅能模拟心血管组织所表现出的非线性机械性能，还能模拟其各向异性行为。通过在PVA样品进行低温热循环时施加可控应变，我们能够在PVA水凝胶中产生定向机械性能。所制备的PVA水凝胶（10%PVA，第3次循环，75%初始应变）同时匹配了猪主动脉的定向应力-应变特性。这种新技术允许对PVA水凝胶进行可控的各向异性引入，并为特定医疗设备应用提供广泛的机械性能控制。
