Effect of thermal treatments on the structural change and the hemostatic property of hair extracted proteins

Human hair is a readily available source for hair protein-based biomaterial and is increasingly explored as an alternative to existing hemostatic materials. The hair protein is a complex mixture of multiple proteins, which are preferably extracted at relatively high temperatures (50−90 °C) for increasing protein yields. However, the effect of processing temperature on the hemostatic property of the hair derived proteins are not yet well-understood. The objective of the current study was to characterize the influence of thermal treatments (37 °C, 50 °C, 75 °C, 80 °C, and 90 °C) on the (i) secondary structure of different fractions of hair proteins including keratin (40−65 kDa) and keratin-associated proteins (KAPs, 6−30 kDa), and (ii) their capability to precipitate the soluble fibrinogen in an in vitro fibrin clotting assay. Our results indicated that the thermal treatments induced changes to the helical contents of hair-derived protein extracts and also increased the precipitation amount and rate of soluble fibrinogen. While further studies are required to better understand the exact role of hair protein fractions on the coagulation process, the current research suggests that the hair proteins extracted under relatively high temperatures is a prerequisite approach for improving the hemostatic property of human hair-derived proteins.