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Wrap Your Hair Around Biotechnology

Need to repair damaged hair? Biotechnology may be the way to go.

What comes to mind when you think of biotechnology? Maybe it’s Dolly the cloned sheep, or GMOs, or stem cell therapy, or DNA profiling, or mRNA vaccines. Rightly so. These are indeed examples of biotechnology, defined as the “manipulation of living organisms, or of substances produced by living organisms, with an aim towards developing useful agricultural, industrial or medical products.” But how about a lotion formulated to repair damaged hair? Probably not something you would connect to biotechnology. Just wait and see. First, though, a quick lesson on the chemistry of hair. 

The basic structural material of hair is the protein keratin, a long, coiled chain of amino acids. The strength and shape of the hair fiber is attributed to adjacent molecules of keratin forming attachments to each other. Hydrogen atoms attached to nitrogen on one protein are attracted to oxygen atoms on a neighbouring protein. These “hydrogen bonds” are weak and easily broken by heat or moisture. Not so for sulfur-sulfur bonds. One of the common amino acids found in keratin is cysteine which has a sulfur atom that can link with a sulfur in a cysteine in an adjacent chain to form a strong sulfur-sulfur bond. If straight hair is to be curled, or curly hair straightened, these bonds have to be cleaved and then reformed once the hair has been combed straight or twisted around curlers. 

Back in the 1870s, Marcel Grateau in France came up with a way to style hair with an early version of a curling iron. As hair was wound around a heated iron rod, the hydrogen bonds were broken and then reformed as the iron cooled, holding the hair in the new shape. Heat can also break some of the sulfur-sulfur bonds, and these can reconnect with help from oxygen in the air. However, there was a problem. Exposure to moisture severs the newly formed hydrogen bonds and the hair fiber springs back to its original shape. That was addressed by German inventor Karl Nessler whose interest in hair is said to have stemmed from observing the curly nature of sheep’s wool.  

At the time it was not unusual to soak wool in urine to degrease it, and it seems Nessler noted that the wool fibers straightened after such treatment. He began to experiment and found that soaking hair in cow’s urine followed by exposure to heat allowed the hair to hold its shape longer. The first permanent was born! Then Nessler found that sodium hydroxide, or “lye,” worked even better. At the time, he had no way of understanding the chemistry but now we know that alkaline materials such as urine or lye readily break sulfur-sulfur bonds. Once these were reformed after the hair had been wound on rollers, they would hold the hair in its new shape because sulfur-sulfur bonds are stable to moisture.  

However, there was still an issue. The rollers had to be first heated with a flame and hair had to stay wound on the rollers for hours. Not only was this inconvenient, there was also the risk of burning the scalp with the hot rollers. Nessler then designed the first “permanent machine” that cleverly suspended each brass roller from an overhead chandelier-like contraption with a cable attached to a counterweight to prevent contact with the scalp. His wife served as the guinea pig for testing the device and suffered burns to hair and scalp before Nessler made the necessary adjustments. Finally, in 1906, he demonstrated the device to hairdressers in London. The next improvement was attaching electrical wires to the brass rollers so they could be heated. It was much easier to wind hair onto cold rollers, dowse it with a lye solution, and then just turn on the current. After women sat for a couple of hours looking as if their head were attached to some medieval torture device, the rollers were unwound, and ladies went home happy with their sculpted waves. 

Electrical engineer Arnold Willat started out by making improvements on the permanent wave machine but thought that there had to be a better way to curl hair, one that did not require sitting in a chair for hours attached to a tangled mass of wires and cables. In 1938, he came up with the first “cold wave” system. First, hair was treated with a solution of ammonium thioglycolate, a chemical that breaks sulfur-sulfur bonds. Then, as the hair was wrapped around rods, the keratin molecules conformed to the new shape. Next came treatment with hydrogen peroxide that reconnected the sulfur atoms, permanently maintaining the style. Of course, “permanently” meant until there was new hair growth. The process was so successful that Willat offered a prize of $1000 to the first woman whose hair he could not curl and never had to pay.   

American chemist and hair-care products entrepreneur Jheri Redding, known as the “Godfather of Hair,” inventor of hair conditioner, and author of “The Anatomy of a Permanent Wave,” adapted the cold wave process to black hair and introduced the “Jheri curl.” Small rods allowed for tighter curls, but maintenance required using a daily moisturizer and sleeping with a plastic cap. The Jheri curl was made famous by Michael Jackson who sported the curly locks in his iconic 1983 music video, “Thriller.” 

Although permanents did deliver the goods, the caustic chemicals also damaged hair, something with which consumers were not thrilled. Permanent hair dyes, introduced in the 1920s, also relied on alkalizing and oxidizing agents that were capable of damaging hair. Such damage occurs when too many sulfur-sulfur bonds are disrupted, and when some of the peptide bonds that link amino acids in keratin are broken. That problem spurred the development of “hair repair” products.  

Keratin treatments involve applying keratin extracted from wool and fusing it to keratin in the hair fibers to improve the texture. This can be done with heat, or more effectively, by linking the applied keratin to the existing keratin with formaldehyde. But that raises toxicity issues since formaldehyde is a carcinogen and irritant. Olaplex, launched in 2014, introduced a novel method of repairing hair with its active ingredient, bis-aminopropyl diglycol dimaleate, a chemical that forms a bridge between disconnected sulfur atoms. Most users called it a game-changer, but some allege that ingredients in the product can cause allergic contact dermatitis resulting in hair loss and injuries to the scalp. The manufacturer retorts that exhaustive safety tests have found no support for the allegation.  

Now we come to biotechnology and a product, K18, touted as a “biomimetic” that “works at the innermost layers of the hair fiber to reconnect broken polypeptide chains, restoring hair strength and elasticity.” How does it do that? The secret lies in “keratin associated peptides.” Peptides are short chains of amino acids and “keratin associated peptides” lurk in-between strands of keratin and their cysteine components form attachments to cysteines in both keratin strands. These attachments are also broken during the perming process and reform after. Now, imagine if the amino acid sequence in keratin were to be analyzed, and the position of the cysteine components determined, then peptides with just the right spacing of cysteines could be synthesized to match the cysteine positions in keratin. Rubbing these peptides into the hair would then strengthen the bonds between keratin molecules. Furthermore, if there were a break in the bonds holding together the amino acids in the keratin chain, the “keratin associated peptides” could attach to both sides of the break and hold the strands together.  

Next, imagine that you don’t have to imagine this. The sequencing of keratin has been done and these days peptides can be readily synthesized. It turns out that peptides that contain ten amino acids, termed “decapeptides,” with the appropriate positioning of cysteines fit the bill. And that is what is contained in K18. Why K18? Likely because eighteen different amino acids are used to synthesize the different decapeptides. So far, reviews have been very good, claiming thicker, silkier hair and application that takes just four minutes compared with a more complicated process for Olaplex.  

Finally, why is K18 a product of biotechnology? Because determining the structure of keratin and the keratin associated proteins is based on identifying the genes in DNA that code for the production of these proteins. DNA is the product of a living organism, hence the “bio.” The analysis in this case leads to the production of a practical product for the hair, which is what “technology” is all about. Hence, we have yet another example of biotechnology. 


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