Department of Mechanical Engineering, University of Vermont, Burlington, Vermont 05405.
Civil and Environmental Engineering Department, University of Vermont, Burlington, Vermont 05405.
Biointerphases. 2020 Sep 22;15(5):051004. doi: 10.1116/6.0000381.
Poly(vinyl alcohol) (PVA), a synthetic, nontoxic polymer, is widely studied for use as a biomedical hydrogel due to its structural and physicomechanical properties. Depending on the synthesis method, PVA hydrogels can exhibit a range of selected characteristics-strength, creep resistance, energy dissipation, degree of crystallinity, and porosity. While the structural integrity and behavior of the hydrogel can be fine-tuned, common processing techniques result in a brittle, linear elastic material. In addition, PVA lacks functionality to engage and participate in cell adhesion, which can be a limitation for integrating PVA materials with tissue in situ. Thus, there is a need to further engineer PVA hydrogels to optimize its physicomechanical properties while enhancing cell adhesion and bioactivity. While the inclusion of gelatin into PVA hydrogels has been shown to impart cell-adhesive properties, the optimization of the mechanical properties of PVA-gelatin blends has not been studied in the context of traditional PVA hydrogel processing techniques. The incorporation of poly(ethylene glycol) with PVA prior to solidification forms an organized, cell instructive hydrogel with improved stiffness. The effect of cryo-processing, i.e., freeze-thaw (FT) cycling was elucidated by comparing 1 FT and 8 FT theta-cryo-gels and cryo-gels. To confirm the viability of the gels, human mesenchymal stem cell (hMSC) protein and sulfated glycosaminoglycan assays were performed to verify the nontoxicity and influence on hMSC differentiation. We have devised an elastic PVA-gelatin hydrogel utilizing the theta-gel and cryo-gel processing techniques, resulting in a stronger, more elastic material with greater potential as a scaffold for complex tissues.
聚乙烯醇（PVA）是一种合成的、无毒的聚合物，由于其结构和物理机械性能，被广泛研究作为生物医学水凝胶。根据合成方法的不同，PVA 水凝胶可以表现出一系列特定的特性，如强度、抗蠕变性、能量耗散、结晶度和孔隙率。虽然水凝胶的结构完整性和行为可以进行微调，但常见的加工技术会导致脆性、线性弹性材料。此外，PVA 缺乏与细胞黏附的功能，这可能限制了将 PVA 材料与组织原位整合。因此，需要进一步对 PVA 水凝胶进行工程设计，以优化其物理机械性能，同时增强细胞黏附和生物活性。虽然在 PVA 水凝胶中加入明胶已被证明可以赋予细胞黏附特性，但在传统 PVA 水凝胶加工技术的背景下，尚未研究 PVA-明胶混合物的机械性能优化。在凝固前将聚乙二醇（PEG）与 PVA 结合，形成具有改进的刚性和组织导向性的有序水凝胶。通过比较 1 次和 8 次冷冻-解冻（FT）循环的θ-冷冻凝胶和冷冻凝胶，阐明了冷冻处理（即冻融）的效果。为了确认凝胶的生存能力，进行了人骨髓间充质干细胞（hMSC）蛋白和硫酸化糖胺聚糖测定，以验证其非毒性和对 hMSC 分化的影响。我们利用θ-凝胶和冷冻凝胶加工技术设计了一种弹性 PVA-明胶水凝胶，得到了一种更强、更有弹性的材料，作为复杂组织支架具有更大的潜力。
