Enzymatic Synthesis of Biosafe Hematoxylin Dyes on Hair: Enhanced Post-Dyeing Hair Health and Boosting Color Fastness

The study presents a novel, eco-friendly hair dyeing method using laccase-catalyzed polymerization of hematoxylin, which avoids harmful chemicals like p-phenylenediamine (PPD) and heavy metal mordants. This enzymatic process, conducted under mild conditions, results in a natural reddish-brown color with excellent color fastness, retaining 97% of its color after 50 washes. The dyed hair maintains its tensile strength and gains additional benefits such as antioxidant activity and UV protection, enhancing hair health and mitigating photoaging risks. This method offers a safer and more sustainable alternative to traditional hair dyes.