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.

中文翻译：

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冷冻处理对聚乙烯醇-明胶θ凝胶的机械和生物学特性的影响。

聚乙烯醇 (PVA) 是一种合成的无毒聚合物，由于其结构和物理机械特性，被广泛研究用作生物医学水凝胶。根据合成方法的不同，PVA 水凝胶可以表现出一系列选定的特性——强度、抗蠕变性、能量耗散、结晶度和孔隙率。虽然可以微调水凝胶的结构完整性和行为，但常见的加工技术会产生脆性的线弹性材料。此外，PVA 缺乏参与和参与细胞粘附的功能，这可能是将 PVA 材料与组织原位整合的一个限制. 因此，需要进一步设计 PVA 水凝胶以优化其物理机械特性，同时增强细胞粘附和生物活性。虽然已证明将明胶加入 PVA 水凝胶中可赋予细胞粘附特性，但尚未在传统 PVA 水凝胶加工技术的背景下研究 PVA-明胶混合物的机械性能优化。在固化之前将聚（乙二醇）与 PVA 结合形成一种有组织的、具有细胞指导性的水凝胶，其刚度有所提高。通过比较 1 FT 和 8 FT theta-cryo-gels 和cryo-gels 阐明了冷冻处理，即冻融 (FT) 循环的影响。为了确认凝胶的活力，进行了人类间充质干细胞 (hMSC) 蛋白和硫酸化糖胺聚糖测定，以验证无毒性和对 hMSC 分化的影响。我们利用 theta 凝胶和冷冻凝胶加工技术设计了一种弹性 PVA-明胶水凝胶，从而产生更坚固、更具弹性的材料，具有更大的潜力作为复杂组织的支架。