Strategies for Improved Hair Binding: Keratin Fractions and the Impact of Cationic Substructures

The study investigated methods to enhance the binding of keratin-associated proteins (KAP) and α-keratins (Ker) to hair fibers. Preactivation with 6-mercaptonicotinamide significantly improved binding to natural hair, and the presence of 25 mM L-arginine further increased Ker accumulation. Perming impaired Ker binding but had minimal effects on preactivated KAP, with enhanced penetrability observed in permed hair. The findings suggested that chemical modifications and additives, such as L-arginine and thiol preactivation, could improve keratin binding and hair restoration, informing the design of keratin-based hair care products.