Keratin (KRT), a natural fibrous structural protein, can be classified into two categories: “soft” cytosolic KRT that is primarily found in the epithelia tissues (e.g., skin, the inner lining of digestive tract) and “hard” KRT that is mainly found in the protective tissues (e.g., hair, horn). The latter is the predominant form of KRT widely used in biomedical research. The oxidized form of extracted KRT is exclusively denoted as keratose (KOS) while the reduced form of KRT is termed as kerateine (KRTN). KOS can be processed into various forms (e.g., hydrogel, films, fibers, and coatings) for different biomedical applications. KRT/KOS offers numerous advantages over other types of biomaterials, such as bioactivity, biocompatibility, degradability, immune/inflammatory privileges, mechanical resilience, chemical manipulability, and easy accessibility. As a result, KRT/KOS has attracted considerable attention and led to a large number of publications associated with this biomaterial over the past few decades; however, most (if not all) of the published review articles focus on KRT regarding its molecular structure, biochemical/biophysical properties, bioactivity, biocompatibility, drug/cell delivery, and in vivo transplantation, as well as its applications in biotechnical products and medical devices. Current progress that is directly associated with KOS applications in tissue regeneration and drug delivery appears an important topic that merits a commentary. To this end, the present review aims to summarize the current progress of KOS-associated biomedical applications, especially focusing on the in vitro and in vivo effects of KOS hydrogel on cultured cells and tissue regeneration following skin injury, skeletal muscle loss, peripheral nerve injury, and cardiac infarction.

角蛋白 (KRT) 是一种天然纤维结构蛋白，可分为两类：主要存在于上皮组织（例如皮肤、消化道内壁）中的“软”胞质 KRT 和“硬”KRT，即主要存在于保护组织（如头发、角）中。后者是广泛用于生物医学研究的 KRT 的主要形式。提取的 KRT 的氧化形式专门称为角糖 (KOS)，而 KRT 的还原形式称为角蛋白 (KRTN)。KOS 可以加工成各种形式（例如，水凝胶、薄膜、纤维和涂层）用于不同的生物医学应用。与其他类型的生物材料相比，KRT/KOS 具有许多优势，例如生物活性、生物相容性、可降解性、免疫/炎症特权、机械弹性、化学可操作性和易于获取。因此，在过去的几十年里，KRT/KOS 引起了相当大的关注，并导致了大量与这种生物材料相关的出版物；然而，大多数（如果不是全部）已发表的评论文章都集中在 KRT 的分子结构、生化/生物物理特性、生物活性、生物相容性、药物/细胞递送和体内移植及其在生物技术产品和医疗器械中的应用。与 KOS 在组织再生和药物输送中的应用直接相关的当前进展似乎是一个值得评论的重要话题。为此，本综述旨在总结目前 KOS 相关生物医学应用的进展，特别关注KOS 水凝胶对皮肤损伤、骨骼肌损失、周围神经损伤后培养细胞和组织再生的体外和体内作用。 , 和心肌梗塞。