By Shin Hee Lee* and Anthony D. Sabatelli** --
"Your hair is your crowning glory" is an often-quoted phrase with biblical roots.1 Perhaps more importantly, one's hair is a visible barometer of one's health and age. Hair care products are also big business. The global hair care market reached $85.5 billion in annual sales in 2017. This figure is expected to climb to over $100 billion by 2024. The U.S. hair care market outcompeted the Asia-Pacific market in 2017, now making it the largest market in the world at about $15 billion. This highly lucrative hair care market continues to grow rapidly with advances in nanotechnology and other areas. A sampling of patents from the hair care sector is summarized at the end of this article.
Today, there is an enormous array of hair products consumers can buy to satisfy their hair care needs. In addition to implements and devices, hair care products can be classified into four categories: hair care, hair styling, hair coloring, and perms/straighteners. The hair care category umbrellas shampoos, conditioners, hair sprays, and hair treatments (e.g., anti-dandruff serums). The hair styling category includes hair sprays, heat protectors, gels, mousses, and cremes. Loréal, Procter and Gamble, Coty, Shiseido, Avon, and Unilever are the key players in the field.
The hair is relatively fine and has a very large total surface area of over 40 square feet on an average head. These properties make the hair easy to handle but make it difficult to apply and remove products after use. Nanotechnology solves many of these problems, so that it is widely employed across all sectors in the hair care field. Nanomaterials, because of their small size, possess the ability to interact with substrates at an atomic or molecular level and are also highly reactive due to their large surface area-to-mass ratio. Furthermore, nanoparticle-based hair care products can penetrate deep inside the hair fiber core to more effectively deliver active ingredients to the hair.
Two-in-one shampoos that are intended to both clean and condition the hair provide an interesting application of nanotechnology. Some two-in-one shampoos are formulated as oil-in-water emulsions containing both surfactants and silicone oils. The surfactants of the shampoo provide a cleansing effect on the surface of the hair fibers and are rinsed away with water, while the silicone oil of the conditioner remains behind to coalesce and diffuse nanosized particles onto and into the hair fibers. These particles provide a conditioning effect on damaged hair strands and restore the hair's glossy texture.
A wide array of biomaterials are also used in hair care products. For example, sericin, a protein derived from silkworms, is currently one of the most promising biomaterials that is used with nanoparticles for conditioners and hair-straightening products. Also, zinc and chitin nanofibril complexes have been shown to exhibit anti-dandruff and oil-control effects by reportedly promoting amino acid synthesis and keratin formation.
A hair treatment product named Olaplex has been gaining immense popularity for effectively recovering damaged hair from the effects of excessive bleaching. It gained public attention after celebrities such as Taylor Swift and Kim Kardashian acclaimed its efficacy. Its key ingredient, bis-aminopropyl diglycol dimaleate, is believed to reconnect broken disulfide sulfur bonds in the cuticle and cortex layers of the hair fibers.
Furthermore, an interesting use of small particles was recently disclosed by Coty. The invention uses small particles as free radical scavengers to protect and treat skin or hair damage, particularly due to chemotherapy.
"Dry" shampoos are a relatively new product category (although some have been around since at least the 1960s). These products coat the hair with oil-absorbing powders to give the hair a fresher and cleaner appearance without the use of water. Living Proof is one of the leading dry shampoo makers. Leave-in conditioners have also gained enormous popularity. Hair care product companies Unite and It's-A-10 currently have the top-selling leave-in conditioners in the market.
The hair coloring sector is a multi-billion-dollar industry that benefits largely from nanotechnology. Nanotechnology has been providing healthy and more effective alternatives for traditional synthetic dyes such as p-phenylenediamine (PDA), which have been implicated with health problems such as various cancers, non-Hodgkin's lymphoma, and multiple myeloma. Recently, researchers found that the incorporation of PDA in hyaluronic nanoparticles reduces the potential toxicity compared to PDA alone. In addition, quantum dot luminescent nanoparticles have been shown to permanently change the hair's color without damaging the keratin proteins of the hair. Even though new hair products are constantly entering the market, there are still a number of challenges. For example, many hair coloring products are not permanent enough, and fade or wash out. Also, while it is easy to darken light-colored hair, it is far more difficult to go in the other direction to lighten dark-colored hair, without a pre-bleaching step.
The use of nanotechnology in hair care even extends to devices such as hair dryers. Sophisticated hair dryers such as the Panasonic nanoeTM dryer claim to emit and deliver nano-sized charged particles onto the hair and scalp to tighten hair cuticles, moisturize the scalp, and improve hair shine. Also, silver nanoparticles have been found to exhibit antibacterial and antifungal properties that minimize the spread of bacteria on the scalp. Ceramic nanoparticles have been found to promote smooth, silky hair.
Shown below is a table summarizing just a sampling of patents for hair care products, some of which go back to the 1980's.
1 King James Version Bible, 1 Corinthians 11:15, "But if a woman have long hair, it is a glory to her."
* Shin Hee Lee is a Ph.D. Candidate in the Chemistry Department at Yale University. She is currently associated with the Yale Energy Sciences Institute, where she specializes in organic synthesis of novel light-harvesting dye molecules for solar cells. Prior to attending Yale, Shin Hee obtained her B.S. in Chemistry with High Honors at the University of Michigan – Ann Arbor, during which she published patents and papers on developing synthetic methodologies for fluorinated small molecules.
** Dr. Sabatelli is a Partner with Dilworth IP
For additional information regarding this topic, please see:
• "Patent Beauty: IP and the Cosmeceutical Industry," May 3, 2018
• "Nanomedicine: A Vast Horizon on a Molecular Landscape -- Cosmeceuticals," June 6, 2018
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