Chitin nanofibrils (CNs) are an emerging bio-based nanomaterial. Due to nanometric size and high crystallinity, CNs lose the allergenic features of chitin and interestingly acquire anti-inflammatory activity. Here we investigate the possible advantageous use of CNs in tympanic membrane (TM) scaffolds, as they are usually implanted inside highly inflamed tissue environment due to underlying infectious pathologies. In this study, the applications of CNs in TM scaffolds were twofold. A nanocomposite was used, consisting of poly (ethylene oxide terephthalate)/(polybutylene terephthalate) (PEOT/PBT) copolymer loaded with CN/polyethylene glycol (PEG) pre-composite at 50/50 (w/w %) weight ratio, and electrospun into fiber scaffolds, which were coated by CNs from crustacean or fungal sources via electrospray. The degradation behavior of the scaffolds was investigated during 4 months at 37 °C in an otitis-simulating fluid. In vitro tests were performed using cell types to mimic the eardrum, i.e., human mesenchymal stem cells (hMSCs) for connective, and human dermal keratinocytes (HaCaT cells) for epithelial tissues. HMSCs were able to colonize the scaffolds and produce collagen type I. The inflammatory response of HaCaT cells in contact with the CN-coated scaffolds was investigated, revealing a marked downregulation of the pro-inflammatory cytokines. CN-coated PEOT/PBT/(CN/PEG 50:50) scaffolds showed a significant indirect antimicrobial activity.

中文翻译：

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几丁质纳米纤维在鼓膜支架中的应用以调节炎症和免疫反应

几丁质纳米纤维（CNs）是一种新兴的生物基纳米材料。由于纳米尺寸和高结晶度，CNs 失去了几丁质的过敏特性，有趣的是获得了抗炎活性。在这里，我们研究了 CNs 在鼓膜 (TM) 支架中的可能有利用途，因为它们通常由于潜在的传染性病变而植入高度发炎的组织环境中。在这项研究中，CNs 在 TM 支架中的应用是双重的。使用了一种纳米复合材料，由聚（环氧乙烷对苯二甲酸酯）/（聚对苯二甲酸丁二醇酯）（PEOT/PBT）共聚物组成，负载为 50/50（w/w）的 CN/聚乙二醇 (PEG) 预复合材料%) 重量比，并电纺成纤维支架，通过电喷雾由甲壳类动物或真菌来源的 CNs 包覆。在 4 个月内在 37°C 下在模拟耳炎的液体中研究了支架的降解行为。体外测试使用细胞类型来模拟鼓膜，即结缔组织使用人类间充质干细胞 (hMSC)，上皮组织使用人类真皮角质形成细胞 (HaCaT 细胞)。HMSCs 能够定植支架并产生 I 型胶原蛋白。研究了与 CN 涂层支架接触的 HaCaT 细胞的炎症反应，揭示了促炎细胞因子的显着下调。CN 涂层的 PEOT/PBT/(CN/PEG 50:50) 支架显示出显着的间接抗菌活性。