Tuning the Range of Polyacrylamide Gel Stiffness for Mechanobiology Applications
Tuning the Range of Polyacrylamide Gel Stiffness for Mechanobiology Applications
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DOI：
10.1021/acsami.5b09344
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发表时间：
2016-08-31
影响因子：
9.5
通讯作者：
Pruitt, Beth L.
中科院分区：
文献类型：
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作者：
Denisin, Aleksandra K.;Pruitt, Beth L.
调节聚丙烯酰胺凝胶中的丙烯酰胺单体和交联剂含量可控制水凝胶的刚度，但报道的相同制剂的弹性模量变化很大，这些差异通常归因于不同的测量方法。很少有研究使用相同的表征平台检查单体和交联剂浓度的刚度趋势。在这项工作中，我们使用原子力显微镜和分析力距离曲线推导出的弹性模量，聚丙烯酰胺水凝胶。我们发现，凝胶的弹性模量随着交联浓度的增加而增加，直到一个拐点，之后凝胶刚度随着交联的增加而降低。这种行为的出现是因为形成了高度交联的簇，这增加了网络结构的不均匀性和异质性，导致即使在高交联条件下，全球网络也会软化。我们确定这些拐点为三种不同的总聚合物配方。当我们通过使用低聚合温度来改变凝胶化动力学时，我们发现与室温相比，在4 ° C下聚合时凝胶更硬，这表明凝胶结构，弹性和网络形成之间存在复杂的关系。我们还研究了凝胶硬度在储存10天期间如何变化，并发现特定的凝胶制剂经历了显著的硬化（1.55 +/-0.13），这可以通过初始聚合引起的凝胶溶胀的差异来解释，参数。两者合计，我们的研究强调了聚丙烯酰胺配方，聚合温度，凝胶化时间，和存储时间在定义的聚丙烯酰胺水凝胶的结构和机械性能的重要性。
Adjusting the acrylamide monomer and cross linker content in polyacrylamide gels controls the hydrogel stiffness, yet the reported elastic modulus for the same formulations varies widely and these discrepancies are frequently attributed to different measurement methods. Few studies exist that examine stiffness trends across monomer and cross-linker concentrations using the same characterization platform. In this work, we use Atomic Force Microscopy and analyze force distance curves to derive the elastic modulus, of polyacrylamide hydrogels. We, find that gel elastic modulus increases with increasing cross-link concentration until an inflection point, after which gel stiffness decreases with increasing cross-linking. This behavior arises because of the formation of highly cross-linked clusters, which add inhomogeneity and heterogeneity to the network structure, causing the global network to soften even under high cross-linking conditions. We identify these inflection points for three different total polymer formulations. When we alter gelation kinetics by using a low polymerization temperature, we find that gels are stiffer when polymerized at 4 degrees C compared to room temperature, indicating a complex relationship between gel structure, elasticity, and network formation. We also investigate how gel stiffness changes during storage over 10 days and find that specific gel formulations undergo significant stiffening (1.55 +/- 0.13), which may be explained by differences in gel swelling resulting from initial polymerization,parameters.. Taken together, our study emphasizes the importance of polyacrylamide formulation, polymerization temperature, gelation time, and storage duration in defining the structural and mechanical properties of the polyacrylamide hydrogels.