Cross-evaluation of stiffness measurement methods for hydrogels
Cross-evaluation of stiffness measurement methods for hydrogels
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DOI：
10.1016/j.polymer.2022.125316
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发表时间：
2022-09
期刊：
影响因子：
4.6
通讯作者：
N. Richbourg;M. Rausch;N. Peppas
中科院分区：
文献类型：
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作者：
N. Richbourg;M. Rausch;N. Peppas
刚度是水凝胶的关键性质，影响细胞粘附、运动性和分化、生物医学植入物的完整性以及伤口覆盖物的柔性。水凝胶的刚度由其合成条件控制，无论是通过改变所使用的聚合物或交联方案，增加聚合物的浓度，还是增加交联程度。然而，没有通用的设计方案，控制水凝胶刚度已被提出，不同的研究之间的比较受到不一致的测量方法。在这里，我们使用的结构模型，使十八个聚（乙烯醇）水凝胶配方的刚度的先验预测和比较五个独立的刚度测量方法，建立广泛适用的标准，预测和测量水凝胶的刚度。五种测量方法（拉伸、压缩、剪切流变学、宏观压痕和纳米压痕）之间的总体刚度差异很小，但每种方法都提供了不同的见解，包括泊松比和粘弹性的测量。所测量的水凝胶刚度随着初始聚合物体积分数（φ 0）的增加而增加，并且随着连接点之间的聚合度（Nj）的增加而降低，与基本预测相匹配。水凝胶中的溶胀和刚度之间的强相关性提出了用于提高预测模型的准确性的机制。这些结果表明，我们的预测模型是一个强大的工具，合理设计的水凝胶具有理想的刚度，为各种生物医学应用。
Stiffness is a key property for hydrogels, affecting cellular adhesion, motility, and differentiation, the integrity of biomedical implants, and the flexibility of wound coverings. A hydrogel's stiffness is controlled by its synthesis conditions, whether by changing the polymer or crosslinking scheme used, increasing the concentration of polymer, or increasing the extent of crosslinking. However, no universal design scheme for controlling hydrogel stiffnesses has been previously proposed, and comparisons between different studies are limited by inconsistent measurement methods. Here, we used a structural model to make a priori predictions of the stiffness of eighteen poly (vinyl alcohol) hydrogel formulations and compared five independent stiffness measurement methods to establish broadly applicable standards for predicting and measuring the stiffness of hydrogels. Overall stiffness differences between the five measurement methods (tension, compression, shear rheology, macroindentation, and nanoindentation) were small, but each method provided distinct insights, including measurements of Poisson's ratio and viscoelasticity. The measured hydrogel stiffnesses increased with increasing initial polymer volume fractions (φ 0) and decreased with increasing degrees of polymerization between junctions (N j), matching fundamental predictions. Strong correlations between swelling and stiffness in hydrogels suggested a mechanism for improving the accuracy of the predictive model. These results suggest that our predictive model is a powerful tool for the rational design of hydrogels with desirable stiffnesses for a variety of biomedical applications.