Just a few years ago, scientists developed a milder graphene dye,media reported. And now researchers have succeeded in using another less exotic substance– synthetic melanin. Typically, hair dyes include components such as hydrogen peroxide, ammonia and small molecular dyes. These ingredients are used to penetrate the outer cortex of each hair, allowing the colorant to be deposited inside. The use of these dyes can damage hair over time and can also cause allergic reactions to customers and hairstylists.
Melanin is a naturally occurring pigment that gives us the color of our hair. As you age, it disappears from the hairs, causing them to appear gray. Researchers have tried to use synthetic melanin as a substitute for traditional dyes. Unfortunately, in order for it to effectively color the hair, a high concentration of toxic heavy metals and oxidants is required.
Led by postdoctoral researchers Claudia Battistella and Professor Nathan Gianneschi, the team from Northwestern University in Illinois has now developed a way to replace these metals and oxidants with low heat and a small amount of ammonium hydroxide. By increasing the concentration of the latter, natural dark tones can be produced, while red and gold can be achieved by adding a little hydrogen peroxide. In laboratory tests of hair samples, they did not fade after 18 rinses.
The study was described in a recent paper published in the journal ACS Central Science.