Bioinspired Chemoenzymatic Route to Artificial Melanin for Hair Pigmentation

Abstract

Recent reports suggest that next-generation hair dyes might take inspiration from the natural pigment melanin. In humans, melanin imparts color to hair and skin and acts as a natural sunscreen and radical scavenger, thereby protecting lipids and proteins from damage. The most commonly employed synthetic mimic of melanin is polydopamine, and its successful deposition on human hair was recently reported. Herein, we describe an enzymatic approach to synthetic melanin for dyeing human hair in a process that closely mimics part of natural melanogenesis. This chemoenzymatic method avoids the addition of a base and enables the implementation of several monomers beyond dopamine, including tyrosine, tyramine, and their derivatives. Critically, the enzyme provides a milder process for producing coated hair fibers than conventional chemical hair dyeing methods. In addition to providing natural coloration, these coatings have the potential to act as protective sunscreens that prevent photodamage of the inner hair fibers during exposure to sunlight. The protocols developed herein represent a mild and efficient route to nature-inspired multifunctional coatings. Such materials are promising candidates for artificial hair pigmentation and, more generally, could find extensive application as functional fiber coatings.

Analysis of the Formation of Sauce-Flavored Daqu Using Non-targeted Metabolomics

“…Thus, enzymatic browning was also one factor responsible for the formation of BQ. Melanin has many excellent properties, such as strong free radical scavenging ability ( Ma et al, 2018 ), resistance to ultraviolet radiation ( Ye et al, 2019 ), heat resistance ( Li et al, 2019 ), and antibacterial ( Vasanthabharathi et al, 2011 ) and cell protection ( Langfelder et al, 2003 ), and can be used as antioxidants ( Zhao et al, 2022 ), anti-tumor drugs ( Ye et al, 2019 ), and hair dyes ( Battistella et al, 2020 ). Therefore, studies aimed at screening of melanin-producing bacteria from Daqu and identifying the melanin structure and function are needed.…”

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

“…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 …”

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].…”