Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66045, USA.
Tissue Eng Part B Rev. 2013 Oct;19(5):403-12. doi: 10.1089/ten.TEB.2012.0461. Epub 2013 Apr 4.
Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context.
关节软骨损伤会给患者带来严重的疼痛和高昂的医疗费用。不幸的是，软骨修复策略一直以来都不可靠且/或复杂。基于生物材料的组织工程策略具有很大的前景，包括使用水凝胶来再生关节软骨。机械完整性可以说是工程软骨最重要的功能结果，尽管迄今为止基于水凝胶的构建体的机械测试主要集中在变形而不是失效特性上。除了变形测试之外，随着软骨组织工程领域的成熟，鉴于工程构建体成功的关键临床重要性，该领域将受益于将机械失效测试添加到结果分析中。然而，用于评估水凝胶和关节软骨机械失效的方法存在巨大差异。为了弥合关节软骨和水凝胶机械测试方法之间的差距，本综述对每种方法的不同韧性测量进行了分类。确定这两个截然不同领域之间共同点的紧迫性很高，因为机械失效已经准备好与刚度一起成为功能设计要求。在比较水凝胶和软骨之间的韧性测量方法时，我们建议，基于单边切口试验的拉伸试验可能是评估软骨组织工程中水凝胶基构建体机械失效的最佳选择，部分原因是因为试样制备更简单，并且可以在断裂力学背景下采用相关的美国材料与试验协会 (ASTM) 标准。
