Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, USA.
Biomaterials. 2010 Feb;31(4):585-93. doi: 10.1016/j.biomaterials.2009.09.076. Epub 2009 Oct 12.
Keratins are a family of structural proteins that can be isolated from a variety of tissues. "Soft" keratins are cytoskeletal elements found in epithelial tissues while protective tissues such as nails, hooves, and hair are composed of "hard" keratins. Hard keratins have been the subject of biomaterials investigations for more than three decades. Numerous methods exist for denaturing these proteins which are characterized by a high sulfur content and extensive disulfide bonding, under either oxidative or reductive conditions, extracting them from tissue and processing them into various physical states such as gels, films, coatings, and fibers. Kerateines or keratoses (oxidatively or reductively derived, respectively), alone or in combination with other biomaterials, have been tested in a small number of systems to demonstrate feasibility for medical applications such as wound healing, bone regeneration, hemostasis, and peripheral nerve repair. These investigations have shown generally good compatibility with cells and tissues, but the focus of prior investigations has been fairly narrow, and as a result there is relatively little published data on the general behavior of keratin biomaterials in biological systems beyond cell culture assays. The goal of this study was to produce a reduced form of keratin biomaterial, kerateine, using a typical and well-published technique, and characterize several aspects of its behavior that may have implications to its general use as a biomaterial. Kerateines were extracted from human hair, fabricated into gels and porous scaffolds, characterized, and placed into biological systems to determine their interactions with cells and tissue. Initially, the proteins were analyzed for molecular weight and amino acid content, as well as their ability to facilitate cell adhesion and proliferation. Crosslinked hydrogels were investigated for their hydrolytic stability in vitro; the micro-architecture and in vivo tissue response of lyophilized gels was also studied. These experiments both confirmed and expanded earlier findings that kerateines demonstrate excellent compatibility in biological systems.
角蛋白是一类结构蛋白，可以从各种组织中分离出来。“软”角蛋白是存在于上皮组织中的细胞骨架成分，而指甲、蹄和毛发等保护组织则由“硬”角蛋白组成。硬角蛋白已经成为生物材料研究的主题超过三十年。存在许多方法可以使这些富含硫且二硫键广泛的蛋白质变性，这些方法在氧化或还原条件下，将它们从组织中提取出来，并将其加工成各种物理状态，如凝胶、薄膜、涂层和纤维。角蛋白或角蛋白（分别是氧化或还原衍生的）单独或与其他生物材料结合，已经在少数系统中进行了测试，以证明其在医学应用中的可行性，如伤口愈合、骨再生、止血和周围神经修复。这些研究通常显示与细胞和组织具有良好的相容性，但之前的研究重点相当狭窄，因此，关于角蛋白生物材料在细胞培养测定以外的生物系统中的一般行为的公开数据相对较少。本研究的目的是使用典型且已发表的技术制备还原形式的角蛋白生物材料角蛋白，并表征其行为的几个方面，这些方面可能对角蛋白作为生物材料的一般用途具有重要意义。角蛋白从人类头发中提取出来，制成凝胶和多孔支架，并进行了表征，并将其置于生物系统中，以确定其与细胞和组织的相互作用。最初，对蛋白质的分子量和氨基酸含量以及它们促进细胞黏附和增殖的能力进行了分析。对交联水凝胶的体外水解稳定性进行了研究；还研究了冻干凝胶的微观结构和体内组织反应。这些实验证实并扩展了早期的发现，即角蛋白在生物系统中表现出极好的相容性。
