Melanin-mimetic multicolor and low-toxicity hair dye

Abstract

This study developed novel approaches for melanin-mimetic multicolor and low-toxicity hair dye through rapid deposition of PDA-based coatings on hair.

Colorful Pigments for Hair Dyeing Based on Enzymatic Oxidation of Tyrosine Derivatives

“…First, there are no organic solvents or toxic aromatic amine-based colorants in this amino acid-based formulation. Second, tyrosine derivatives are analogues of natural eumelanin, which should have good biocompatibility and negligible toxicity in vitro and in vivo. ,,, Meanwhile, it has been proved that the highly hydrophilic precursor DA and the synthesized insoluble biomimetic melanin are unlikely to penetrate the skin barrier due to their high molecular weight. , …”

“…Therefore, the use of melanin to reconstruct the color of hair fibers is a fundamentally feasible method to darken hair. With a complex structure and composition, natural melanin is difficult to separate and purify from the biological environment, and the self-assembly and polymerization of natural melanin are regulated through complex pathways, in a process that is not fully understood. − Nowadays, strategies to control the biomimetic synthesis and regulation of artificial melanin pigments have been continuously proposed, which is relatively cheap, feasible, and scalable. , Recently, the biomimetic chemical oxidation technology can produce melanin intermediates, which can be used as a new type of hair dye for black coloring. , However, the oxidation process of the selected polydopamine (PDA) requires the addition of ammonia, H 2 O 2 , and metal ions, which cannot meet the requirements of green chemistry and practical applications. − Compared with traditional chemical dyes, the use of tyrosinase (EC 1.14.18.1) for enzymatic oxidation has many advantages including environmental friendliness, simple dyeing, and easy handling. − Therefore, reports on the use of biological enzymatic methods for hair dyeing have increased in recent years. − However, the colors that can be produced by the existing methods for synthesizing melanin pigments are usually darker colors such as black, and it is still a long-term goal that people pursue to obtain a full spectrum of rich colors …”

A review of developments in industrial hair colorant actives for oxidative dyes

“…In addition, no application‐relevant toxicology was presented. Periodate‐based oxidative polymerisation of DA and application of the resultant PDA in a sol‐gel medium was discovered to be capable of furnishing coloration of a wider palette than the very limited gamut of previous PDA‐related studies 163 . Varying oxidation conditions or co‐polymerising DA with cysteine enabled colour to be tuned to a range of permanent reddish as well as brownish shades.…”

Iron Gall Ink Revisited: A Surfactant-Free Emulsion Technology for Black Hair-Dyeing Formulation

“…Temporal hair coloring is widely used for the coverage of premature graying of hair (PGH) [13] and senile gray hair [14], but public concern on the potential side effects of dyes in the hair-dyeing products, such as allergic reactions and tumorigenesis [15][16][17], leads academic researchers and cosmetic companies to seek for alternatives [18][19][20][21][22][23][24][25][26][27][28]. For example, a mixture of graphene sheets, vitamin C, and chitosan was utilized for the black hairdyeing formulation that had an antistatic property and enhanced thermal conduction [18].…”

“…For example, a mixture of graphene sheets, vitamin C, and chitosan was utilized for the black hairdyeing formulation that had an antistatic property and enhanced thermal conduction [18]. Various biocompatible oxidation conditions for polydopamine deposition to hairs have also been investigated [19][20][21][22][23][24]. In addition, there has been much effort on the functional combination of hair coloring and strengthening (or other hair-boosting functions) based on nature-derived, biofriendly compounds [25].…”