A new technique is described for the construction of core–shell microfibers for biomedical applications. Fibrous scaffolds were fabricated by electrospinning, followed by covalent layer-by-layer deposition based on the rapid bioorthogonal reaction between s-tetrazines (Tz) and trans-cyclooctenes (TCOs). Electrospun poly(ε-caprolactone) (PCL) scaffolds were subjected to surface modifications to install tetrazine groups. The scaffolds were iteratively submerged in aqueous solutions of TCO-modified hyaluronic acid (HA-TCO) and tetrazine-modified hyaluronic acid (HA-Tz), resulting in the controlled growth of a cross-linked HA gel around individual microfibers. Integrin-binding motifs were covalently attached to the surface of the microfibers using TCO-conjugated RGD peptide. The scaffolds fostered the attachment and growth of primary porcine vocal fold fibroblasts without a significant induction of the myofibroblast phenotype. Stimulation with transforming growth factor beta (TGF-β) moderately enhanced fibroblast activation, and inhibition of the Rho/ROCK signaling pathway using Y27632 further decreased the expression of myofibroblastic markers. The bioorthogonally assembled scaffolds with a stiff PCL core and a soft HA shell may find application as therapeutic implants for the treatment of vocal fold scarring.

中文翻译：

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通过生物正交逐层组装的核壳微纤维

描述了一种用于构建用于生物医学应用的核壳微纤维的新技术。通过静电纺丝制造纤维支架，然后基于s-四嗪 (Tz) 和反式之间的快速生物正交反应进行共价层逐层沉积-环辛烯（TCO）。静电纺丝聚 (ε-己内酯) (PCL) 支架经过表面修饰以安装四嗪组。支架被反复浸没在 TCO 修饰的透明质酸 (HA-TCO) 和四嗪修饰的透明质酸 (HA-Tz) 的水溶液中，导致交联的 HA 凝胶在单个微纤维周围的受控生长。使用 TCO 缀合的 RGD 肽将整合素结合基序共价连接到微纤维表面。支架促进原代猪声带成纤维细胞的附着和生长，而没有显着诱导肌成纤维细胞表型。用转化生长因子β（TGF-β）刺激适度增强成纤维细胞活化，使用 Y27632 抑制 Rho/ROCK 信号通路进一步降低了肌成纤维细胞标志物的表达。具有硬质 PCL 核心和软质 HA 壳的生物正交组装支架可用作治疗声带瘢痕的治疗性植入物。