Scientists invented mild hair dye: synthetic imitation natural hair melanin pigmentation
Fuming wrong person shall take off, black hair that was cut to add. Cinnabar deserve force new spring black hair. CSD coming like clouds, the hand tip shoots meat as creamy. Everybody wants a young, eager beautiful, has a beautiful black hair since ancient times countless people willing heart. Human hair is mainly composed of protein, to impart flexibility and softness of hair. Melanin is a natural pigment, mainly in the cortex of the hair shaft or intermediate layer, given the natural beauty of hair color. However, with age, the melanin will reduce or even disappear from the hair fiber, leading to loss of color and whitening. In order to maintain the beautiful black hair,gradually get people of all ages, in recent years, the industry has become one of the hair cosmetics industry the most profitable industry. However, some conventional hair dye components but potentially carcinogenic, and most of hair dyes using aqueous ammonia, hydrogen peroxide, and other small molecule dyes penetrate the epidermis and deposit on the hair, these irritating substances not only damage the hair, but also to the human body cause allergic reactions or other health problems. Recently, at Northwestern University Professor Nathan Gianneschi first reported the synthesis of a new method of melanin in human hair on the effective deposition, and by adjusting the reaction conditions to achieve different colors. compared to conventional dyes, the coloring method mild conditions, but without any metal chelating agent or strong oxidizing agents, maximize the protection of the hair from damage. The researchers succeeded in gold, natural red, brown and gray hair dyed dark brown or black. This approach has the potential to replace the traditional hair dye, providing new opportunities for melanin-based hair dye! Preparation of
the synthesis of melanin
Poly dopamine-based materials are commonly considered to be human hair melanin synthesis mimetic, have been commercially available by various methods dopamine (DA) reports oxidation of melanin synthesis. The researchers found, DA autoxidation in air and has the mildest method of forming a biocompatible polydopamine (PDA) when DA is added to the alkaline solution, the polymerization starts immediately, while the color changed from colorless transparent light brown, and finally to dark brown and black. Thus, DA autoxidation is a synthetic melanin deposition in hairPromising methods using air as the oxidant is not only mild conditions, but also inexpensive and scalable.
Synthesis of melanin dyeing performance
Researchers by adjusting the ammonium concentration and the temperature of the allowable range to obtain various dyeing performance. FIG 2 can be clearly observed dark blond hair, the effect of adding hair dyed with 6% NH4OH and a commercially available natural brown hair dye hair dark brown hair had similar effects. Show that melanin synthesis can be used as a simple and effective hair dye, but without adding any chemical substance irritating and potentially carcinogenic.
persistent hair melanin synthesis Subsequently, researchers have tested the persistence of the color of hair after study dopamine personnel and 6% NH4OH after the hair at 37-40 ° C 2 h, washed 5 times with water, then washed 18 times with shampoo. The results shown in FIG. 3, no signs of discoloration or color change After washing dyed hair melanin synthesis, and washing water was clear, but with the commercial hair dye dyed hair was washed with water, it turned brown. The researchers show that provides a permanent method of hair, dyed hair shampoo can withstand at least 18 times.
versatility the synthesis of melanin
Finally, the researchers characterized the synthesis of melanin hair dyeing performance of different samples to determine the generality of the method. The researchers collected hair samples from four different ages and races. Figure 4 shows a comparison of before and after the hair color, four different colors of hair coloring was successful, highlights the versatility and generality of the method. Furthermore, the method of FIG. 4C is possible to adjust the natural hair to the original brown, confirms this synthetic melanin hair dye as a new potential.
Articles in Benpian, The researchers first demonstrated the synthesis of melanin deposited on human hair, compared to commercially available hair dye, not only without the use of any metal or irritating substances, and mild hair condition, similar to the resulting color and natural hair color, can resistance washed at least 18 times and does not change the mechanical properties of the hair. We believe that this technology is expected to change the way people\’s hair, and provide new opportunities for the development of hair dye industry! Original link: https: //pubs.acs.org/doi/abs/10.1021/acscentsci.0c00068