When you think of all the human hair that gets cut off and discarded every day in salons around the world … well, that's a lot of wasted hair. That said, scientists in India have devised a new technique for extracting compounds from it, for use in products like wound dressings and sunscreen.
Among other things, human hair is composed largely of a protein known as keratin (as are our fingernails) along with a pigment called melanin, which gives it its color.
Although both substances have numerous potential applications, previous attempts to harvest them from hair have either involved toxic chemicals and complicated procedures, or they've only been able to extract one of the compounds or the other. That's where the new technique comes in.
Developed by a team led by Dr. Paulomi Ghosh from India's Presidency University, the "zero-waste" process begins with locks of discarded hair being washed and cut into small pieces. Those little bits are then mixed with an ionic liquid (liquified salt), which breaks the hydrogen bonds that hold the keratin molecules together.
The hair/salt mixture is then heated and poured into a hydrochloric acid solution, causing the melanin to precipitate out – it's then collected. Finally, chemical dialysis is utilized to collect the now-accessible keratin from the solution. The ionic liquid can then be reused several times, with little loss in performance.
Because keratin has previously been shown to play an active part in the healing of wounds, the scientists believe that keratin extracted from hair could be used in wound dressings such as hemostatic bandages.
And because melanin is known to have ultraviolet-light-blocking and antioxidant qualities, it could be utilized in products like sunscreen or UV-blocking window film. Such would reportedly not be possible with other techniques for extracting melanin from hair, as they cause too much damage to the natural structure of the pigment.
A paper on the research was recently published in the journal ACS Omega.
Source: American Chemical Society
