Phenolic acids (PAs) are natural antioxidant agents in the plant kingdom that are part of the human diet. The introduction of naturally occurring PAs into the network of synthetic shape memory polymer (SMP) polyurethane (PU) foams during foam fabrication can impart antioxidant properties to the resulting scaffolds. In previous work, PA-containing SMP foams were synthesized to provide materials that retained the desirable shape memory properties of SMP PU foams with additional antimicrobial properties that were derived from PAs. Here, we explore the impact of PA incorporation on SMP foam antioxidant properties. We investigated the antioxidant effects of PA-containing SMP foams in terms of in vitro oxidative degradation resistance and cellular antioxidant activity. The PA foams showed surprising variability; p-coumaric acid (PCA)-based SMP foams exhibited the most potent antioxidant properties in terms of slowing oxidative degradation in H₂O₂. However, PCA foams did not effectively reduce reactive oxygen species (ROS) in short-term cellular assays. Vanillic acid (VA)- and ferulic acid (FA)-based SMP foams slowed oxidative degradation in H₂O₂ to lesser extents than the PCA foams, but they demonstrated higher capabilities for scavenging ROS to alter cellular activity. All PA foams exhibited a continuous release of PAs over two weeks. Based on these results, we hypothesize that PAs must be released from SMP foams to provide adequate antioxidant properties; slower release may enable higher resistance to long-term oxidative degradation, and faster release may result in higher cellular antioxidant effects. Overall, PCA, VA, and FA foams provide a new tool for tuning oxidative degradation rates and extending potential foam lifetime in the wound. VA and FA foams induced cellular antioxidant activity that could help promote wound healing by scavenging ROS and protecting cells. This work could contribute a wound dressing material that safely releases antimicrobial and antioxidant PAs into the wound at a continuous rate to ideally improve healing outcomes. Furthermore, this methodology could be applied to other oxidatively degradable biomaterial systems to enhance control over degradation rates and to provide multifunctional scaffolds for healing.

中文翻译：

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具有酚酸基抗氧化性能的形状记忆聚合物泡沫

酚酸 (PA) 是植物界的天然抗氧化剂，是人类饮食的一部分。在泡沫制造过程中将天然存在的 PA 引入合成形状记忆聚合物 (SMP) 聚氨酯 (PU) 泡沫的网络可以赋予所得支架抗氧化性能。在之前的工作中，合成了含 PA 的 SMP 泡沫，以提供保留 SMP PU 泡沫所需形状记忆特性的材料，以及源自 PA 的额外抗菌特性。在这里，我们探讨了 PA 掺入对 SMP 泡沫抗氧化性能的影响。我们研究了含 PA 的 SMP 泡沫在体外抗氧化降解性和细胞抗氧化活性方面的抗氧化作用。PA 泡沫显示出惊人的可变性；₂ O ₂。然而，PCA 泡沫在短期细胞试验中不能有效减少活性氧 (ROS)。基于香草酸 (VA) 和阿魏酸 (FA) 的 SMP 泡沫可减缓 H ₂ O _{2中的氧化降解}其程度低于 PCA 泡沫，但它们表现出更高的清除 ROS 以改变细胞活性的能力。所有 PA 泡沫在两周内都表现出 PA 的连续释放。基于这些结果，我们假设 PA 必须从 SMP 泡沫中释放出来才能提供足够的抗氧化性能；较慢的释放可能会提高对长期氧化降解的抵抗力，而较快的释放可能会导致更高的细胞抗氧化作用。总体而言，PCA、VA 和 FA 泡沫为调节氧化降解率和延长伤口中潜在的泡沫寿命提供了一种新工具。VA 和 FA 泡沫可诱导细胞抗氧化活性，通过清除 ROS 和保护细胞来帮助促进伤口愈合。这项工作可以提供一种伤口敷料材料，该材料可以安全地将抗菌和抗氧化 PAs 以连续的速度释放到伤口中，从而理想地改善愈合结果。此外，该方法可应用于其他可氧化降解的生物材料系统，以增强对降解速率的控制并提供多功能支架用于愈合。