Breakable Nanomaterials to Allow Hair Coloring with Natural Dyes

Abstract The use of melanin as a colorant has been significantly limited by its low solubility and the difficulty of penetrating the hair shaft or follicles. However, the proposed nanotechnological approach demonstrates that it is possible to encapsulate a melanin precursor, 5,6‐dihydroxyindole (DHI), within breakable particles and trigger its oxidation into insoluble black melanin, which can be released upon the degradation of the carrier using UV light. This process can be monitored via UV spectroscopy and has also been successfully tested on hair. In fact, when applied to human white hair, the result was a brownish coloration, with melanin naturally formed and adsorbed by the hair. This mild and harmless method shows great promise for the development of nanoparticles capable of penetrating hair follicles, potentially enabling natural hair pigmentation at the roots.