Effective Penetration of Oxidized Keratin-Rebonding Materials Into Hair Shafts Based on Charge Conversion

The study investigates the use of CTA2-BADG, a β-carboxylic acid amide derivative, to repair damaged hair by enhancing the penetration of rebonding materials into hair shafts through a pH-responsive charge conversion strategy. The research demonstrated that CTA2-BADG effectively penetrates hair shafts, reduces surface roughness, and restores the cuticle layer, as confirmed by SEM, ATR-FTIR, TGA, and fluorescence microscopy. Tensile strength tests showed that CTA2-BADG restored mechanical integrity to levels comparable to normal hair. The study involved 30 hair strands per group and confirmed the safety of CTA2-BADG for topical use, showing no cytotoxicity in human cell lines. This approach could also be applied to other keratinous tissues, suggesting potential for broader cosmetic applications.