Luong P T, Browning M B, Bixler R S, Cosgriff-Hernandez E
Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843-3120.
J Biomed Mater Res A. 2014 Sep;102(9):3066-76. doi: 10.1002/jbm.a.34977. Epub 2013 Oct 11.
Hydrogels based on poly(ethylene glycol) (PEG) are increasingly used in biomedical applications because of their ability to control cell-material interactions by tuning hydrogel physical and biological properties. Evaluation of stability after drying and storage are critical in creating an off-the-shelf biomaterial that functions in vivo according to original specifications. However, there has not been a study that systematically investigates the effects of different drying conditions on hydrogel compositional variables. In the first part of this study, PEG-diacrylate hydrogels underwent common processing procedures (vacuum-drying, lyophilizing, hydrating then vacuum-drying), and the effect of this processing on the mechanical properties and swelling ratios was measured. Significant changes in compressive modulus, tensile modulus, and swelling ratio only occurred for select processed hydrogels. No consistent trends were observed after processing for any of the formulations tested. The effect of storage conditions on cell adhesion and spreading on collagen- and streptococcal collagen-like protein (Scl2-2)-PEG-diacrylamide hydrogels was then evaluated to characterize bioactivity retention after storage. Dry storage conditions preserved bioactivity after 6 weeks of storage; whereas, storage in PBS significantly reduced bioactivity. This loss of bioactivity was attributed to ester hydrolysis of the protein linker, acrylate-PEG-N-hydroxysuccinimide. These studies demonstrate that these processing methods and dry storage conditions may be used to prepare bioactive PEG hydrogel scaffolds with recoverable functionality after storage.
基于聚乙二醇（PEG）的水凝胶因其能够通过调节水凝胶的物理和生物学特性来控制细胞与材料的相互作用，而越来越多地应用于生物医学领域。对于制备一种能在体内按原始规格发挥作用的即用型生物材料而言，评估干燥和储存后的稳定性至关重要。然而，尚未有研究系统地探究不同干燥条件对水凝胶成分变量的影响。在本研究的第一部分，聚乙二醇二丙烯酸酯水凝胶经历了常见的处理程序（真空干燥、冻干、水化后再真空干燥），并测定了这种处理对力学性能和溶胀率的影响。仅部分经过处理的水凝胶的压缩模量、拉伸模量和溶胀率发生了显著变化。对于所测试的任何配方，处理后均未观察到一致的趋势。随后评估了储存条件对胶原蛋白和链球菌胶原蛋白样蛋白（Scl2-2）-聚乙二醇二丙烯酰胺水凝胶上细胞黏附和铺展的影响，以表征储存后的生物活性保留情况。干燥储存条件在储存6周后保留了生物活性；而在磷酸盐缓冲液（PBS）中储存则显著降低了生物活性。这种生物活性的丧失归因于蛋白质连接体丙烯酸酯-聚乙二醇-N-羟基琥珀酰亚胺的酯水解。这些研究表明，这些处理方法和干燥储存条件可用于制备储存后具有可恢复功能的生物活性聚乙二醇水凝胶支架。
