Human hair keratin and its-based biomaterials for biomedical applications

Over the past few decades, naturally derived biomaterials have been extensively used in tissue engineering and regenerative medicine owing to their biological function, structural support, excellent biocompatibility, and favorable biodegradability characteristics. Traditionally, keratin has been extracted from wool, feathers, horns, and other animal sources for industrial use, and it has also been used as a biomaterial to develop scaffolds, hydrogels, and other forms for biomedical applications. Recently, keratin extracted from human hair has emerged as a fascinating biomaterial, which as a human-derived protein, exhibits excellent biocompatibility, no immune reaction upon transplantation, good cellular interaction activity, and biodegradability. Recent development of well-defined and proficient processes for human hair keratin extraction has led to the fabrication of various types of keratin-based biomaterials, which have been employed in successful approaches for tissue regeneration. The use of human hair keratin-based biomaterials for translational biomedical applications requires better understanding of the molecular properties and biological function of keratin. This review provides a critical summary of molecular characteristics, cellular interactions, various extraction strategies, and recent advances in biomedical applications of human hair keratin that could be used to improve tissue regeneration for regenerative medicine.