Enzymatic crosslinking of tyrosine is a simple and modular method for adding functional peptides to silk fibroin (SF) hydrogels. Silk fibroin is a naturally derived polymer notable for its robust mechanical properties, biological compatibility, and versatility. Hydrogels fabricated from SF are elastic, optically clear, and have tunable moduli, however, they do not contain native biological epitopes for cell interactions. In this work we demonstrate the attachment of peptides to SF hydrogels through crosslinking of tyrosine with horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). The goal was to understand the utility of this approach and to study how the addition of peptides affects the SF material properties. SF hydrogels conjugated to model peptides with different molecular weights and hydrophobic properties were studied by liquid chromatography/tandem mass spectroscopy (LC-MS/MS) (bond formation), fluorescent imaging (spatial distribution), Fourier transform infrared spectroscopy (FTIR) (protein secondary structure), and rheology (gelation time, modulus). As a proof of concept using a biologically relevant peptide, a peptide containing the cell binding domain Arg-Gly-Asp (RGD) was conjugated to SF, and the density and morphology of primary human fibroblasts were assessed. This work demonstrates a facile method for adding peptides to silk fibroin that can be adopted for a variety of biomaterials applications.

中文翻译：

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酶介导的肽与丝素蛋白的缀合，可轻松实现水凝胶功能化。

酪氨酸的酶促交联是一种将功能性肽添加到丝素蛋白（SF）水凝胶中的简单模块化方法。丝素蛋白是一种天然衍生的聚合物，以其强大的机械性能，生物相容性和多功能性而著称。由SF制成的水凝胶具有弹性，光学透明性，并且具有可调的模量，但是，它们不包含用于细胞相互作用的天然生物表位。在这项工作中，我们证明了酪氨酸与辣根过氧化物酶（HRP）和过氧化氢（H2O2）的交联将肽与SF水凝胶结合。目的是了解这种方法的实用性，并研究肽的添加如何影响SF材料的性能。通过液相色谱/串联质谱（LC-MS / MS）（键形成），荧光成像（空间分布），傅立叶变换红外光谱（FTIR）（蛋白质）研究了与具有不同分子量和疏水特性的模型肽偶联的SF水凝胶二级结构）和流变性（胶凝时间，模量）。作为使用生物学相关肽的概念证明，将含有细胞结合结构域Arg-Gly-Asp（RGD）的肽与SF偶联，并评估原代人成纤维细胞的密度和形态。这项工作证明了一种向丝素蛋白中添加肽的简便方法，该方法可用于多种生物材料应用中。傅立叶变换红外光谱（FTIR）（蛋白质二级结构）和流变学（胶凝时间，模量）。作为使用生物学相关肽的概念证明，将含有细胞结合结构域Arg-Gly-Asp（RGD）的肽与SF偶联，并评估原代人成纤维细胞的密度和形态。这项工作证明了一种向丝素蛋白中添加肽的简便方法，该方法可用于多种生物材料应用中。傅立叶变换红外光谱（FTIR）（蛋白质二级结构）和流变学（胶凝时间，模量）。作为使用生物学相关肽的概念证明，将含有细胞结合结构域Arg-Gly-Asp（RGD）的肽与SF偶联，并评估原代人成纤维细胞的密度和形态。这项工作证明了一种向丝素蛋白中添加肽的简便方法，该方法可用于多种生物材料应用中。