Cosmetic Potential of a Structural Protein Copolymer Based on Silk, Elastin, and Keratin

This study introduces SELP::KP, a biobased copolymer derived from silk, elastin, and keratin, as a promising alternative for hair cosmetics. Expressed in Escherichia coli and purified without chromatography, SELP::KP exhibits a β-sheet-rich structure and high thermal stability. When applied to hair, it penetrates both the cuticle and cortex, enhancing strength and elasticity, with a 34.9% increase in Young’s modulus and a 12.4% improvement in extensibility. It also acts as a safer perming agent, maintaining curl effects with less damage, and reduces combing strength by half, serving as an effective conditioning agent. SELP::KP offers styling benefits and improved hair health, suitable for use as a leave-in treatment or hair mask.