Bacterial infection and oxidative stress remain critical problems for wound closure because they frequently trigger severe complications and delay wound healing. In addition, maintaining a moist microenvironment can promote skin regeneration. In this study, a bilayer hydrogel modified with tannic acid (TA) was constructed to accelerate wound repair. The bilayer hydrogel, composed of a layer with large pores to absorb the fluids and allow gas exchange and small pores to maintain the wound moist and prevent bacterial invasion, was initially developed. Thereafter, TA was introduced into the hydrogel to form a dual crosslinked network and endowed the hydrogel with adhesiveness, antibacterial, and oxidation resistance. In addition, the TA@bilayer hydrogel exhibited shape memory behaviour and self-healing ability due to the hydrogen bonds formed between TA and the bilayer hydrogel. As a result, the TA@bilayer hydrogel significantly promoted wound closure by accelerating collagen deposition, reducing tumour necrosis factor-α (TNF-α) levels, and facilitating the expression of vascular endothelial growth factor (VEGF).

细菌感染和氧化应激仍然是伤口闭合的关键问题，因为它们经常引发严重的并发症并延迟伤口愈合。另外，保持潮湿的微环境可以促进皮肤再生。在这项研究中，构造了单宁酸（TA）改性的双层水凝胶，以加速伤口修复。最初开发了双层水凝胶，其由具有大孔的层组成，可吸收液体并允许气体交换，而小孔可保持伤口湿润并防止细菌入侵。此后，将TA引入水凝胶中以形成双交联网络，并使水凝胶具有粘合性，抗菌性和抗氧化性。此外，由于TA与双层水凝胶之间形成氢键，因此TA @双层水凝胶表现出形状记忆行为和自愈能力。结果，TA @双层水凝胶通过加速胶原蛋白沉积，降低肿瘤坏死因子-α（TNF-α）水平并促进血管内皮生长因子（VEGF）的表达而显着促进伤口闭合。