Preparation and applications of keratin biomaterials from natural keratin wastes.

Keratin is a kind of natural polymer that is abundant in feathers, wool, and hair. Being one of the natural biomolecules, keratin has excellent biological activity, biocompatibility, biodegradability, favorable material mechanical properties, and natural abundance, which exhibit significant biological and biomedical application potentials. At present, the strategies commonly used for preparing keratin from hair, feathers, wool, etc. include physical, chemical, and enzymatic methods. The present article mainly reviews the structure, classification, preparation methods, and the main biological applications of keratin, and these applications cover wound healing, hemostasis, targeted release of tissue engineering drugs, and so on. It is expected to lay the foundations for its future in-depth investigations and wide applications of keratin biomaterials. KEY POINTS: • There are several pathways to prepare biologically active keratin from wool, feathers, and human hair, etc • Promoting blood coagulation by keratin is related to the adhesion and activation of platelets and the aggregation of fibrin • The biological applications of keratin, including wound healing and tissue engineering, are summarized.