Keratin is a natural polymer found in hair fibers, skin, and nails. It has been investigated as a biomaterial since the 1970s, and has more recently been shown to have applications in healthcare such as medical devices and tissue engineering. Keratins are one of few intermediate filament forming proteins and demonstrate a propensity to self-assemble. Keratins extracted and purified from natural sources such as human hair fibers and wool tend to have weak mechanical properties, but can be cross-linked to form more robust structures. When extracting and purifying keratin proteins from natural fibers, the method of extraction is paramount to obtaining materials that retain the ability to self-assemble and form network structures with appreciable mechanical strength. Here, we compare and contrast two methods for purifying keratin extracts—one in which conventional purification methods are used and a second in which solution aggregation is minimized to promote purification of the molecular entities with the highest propensity for self-assembly, dimers of type I and type II hard keratins. Material that underwent the latter, novel extraction method exhibited higher purity in the form of a lower peptide content. Moreover, hydrogels formed from this material were found to demonstrate greater resistance to shear, and interestingly, increased susceptibility to enzymatic degradation in comparison to hydrogels formed from conventionally extracted material. This novel keratin purification method allows for enrichment of compounds with increased self-assembly behavior, and has the potential to overcome limitations noted in other studies where biomaterials fabricated from purified keratins demonstrated inferior mechanical characteristics.

中文翻译：

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不同纯化方法对角质糖生物材料性能的影响

角蛋白是在头发纤维，皮肤和指甲中发现的天然聚合物。自1970年代以来，它就已经作为一种生物材料进行了研究，并且最近被证明可以应用于医疗保健领域，例如医疗设备和组织工程。角蛋白是为数不多的中间丝形成蛋白之一，并且具有自组装的倾向。从人的头发纤维和羊毛等天然来源提取和纯化的角蛋白往往具有较弱的机械性能，但可以交联形成更坚固的结构。从天然纤维中提取和纯化角蛋白时，提取方法对于获得具有自组装能力并形成具有明显机械强度的网络结构的材料至关重要。这里，我们比较和对比了两种纯化角蛋白提取物的方法-一种使用常规的纯化方法，另一种使用最小化溶液聚集以促进具有最高自组装倾向的分子实体（I型和I型二聚体）的纯化II硬角蛋白。经过后者的材料，新颖的提取方法以较低的肽含量形式表现出较高的纯度。此外，与由常规提取的材料形成的水凝胶相比，发现由这种材料形成的水凝胶表现出更大的抗剪切性，并且有趣的是，其对酶促降解的敏感性增加。这种新颖的角蛋白纯化方法可富集具有增加的自组装行为的化合物，