Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan, 113-8656.
Department of Precision Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan, 113-8656.
Langmuir. 2020 May 26;36(20):5554-5562. doi: 10.1021/acs.langmuir.0c00694. Epub 2020 May 15.
Controlling hydrogel surface wettability is of great importance in the viewpoint of engineering biomaterials that are in contact with cells and tissues. However, studies reporting how the hydrogel bulk properties would affect the surface is scarce, and thus it has been difficult to fabricate hydrogels with the desired properties. Also, there has been no effective method to elucidate this, due to the inhomogeneity introduced in the network structure of conventional hydrogels. Here we report our approach in elucidating the relationship between hydrogel physicochemical parameters and surface wettability by using Tetra-PEG gels, which are known to have homogeneous network structure. Specifically, the polymer volume fraction (φ) and the molecular weight () between the cross-links were controlled. The number of anions, cations, and ionic pairs introduced within the hydrogel, were also individually controlled. The surface wettability of the resulting hydrogels was then evaluated. Results showed that surface wettability is largely dependent on the concentration of charged groups that are introduced in the hydrogel bulk, especially those that are not paired and ionically stabilized. Our findings strongly support the fact that with conventional hydrogels, the correlation between surface wettability and its physicochemical properties had not been evaluated appropriately, and thus our insights will contribute significantly to accumulating further knowledge on controlling hydrogel surface wettability.
控制水凝胶表面润湿性在与细胞和组织接触的工程生物材料方面非常重要。然而，关于水凝胶本体性质如何影响表面的研究报告很少，因此很难制造具有所需性质的水凝胶。此外，由于传统水凝胶的网络结构中引入了不均匀性，因此一直没有有效的方法来阐明这一点。在这里，我们报告了我们使用 Tetra-PEG 凝胶阐明水凝胶物理化学参数与表面润湿性之间关系的方法，众所周知，Tetra-PEG 凝胶具有均匀的网络结构。具体而言，控制了聚合物体积分数（φ）和交联点之间的分子量（）。还分别控制了在水凝胶中引入的阴离子、阳离子和离子对的数量。然后评估了所得水凝胶的表面润湿性。结果表明，表面润湿性在很大程度上取决于引入水凝胶本体的带电基团的浓度，特别是那些未配对和离子稳定的基团。我们的发现有力地支持了这样一个事实，即在传统水凝胶中，表面润湿性与其物理化学性质之间的相关性尚未得到适当评估，因此我们的见解将为进一步控制水凝胶表面润湿性的知识积累做出重大贡献。
