For many people, dyeing hair has become a part of everyday life. Demand for hair dye products has been on the rise since the mid to late 20th century. During the pandemic in the first half of 2020, as people were unable to go to the hairdresser's, sales of DIY hair dye products came to an unprecedented level.
Common hair dyes on the market today can be divided into two categories: synthetic hair dyes and natural hair dyes. Natural dyes are obtained by extracting natural pigments from various plants. Consequently, they have long extraction periods, low extraction rates, high extraction costs, and poor dyeing durabilities. Currently, it still has a high price and low market share.
Synthetic hair dyes, on the other hand, usually contains oxidants and pigment precursors. Studies on hair dyes such as those containing p-phenylenediamine, a common pigment precursor, have found that nearly half of the dyes are strong allergens. In an investigation of 46 hair dyes by the European Commissions Scientific Committee on Consumer Products (SCCP), 10 were extreme sensitizers, 13 were strong sensitizers, and 4 were moderate sensitizers. When exposed to nitrogen oxides, the secondary amines in these dyes form nitrosamine derivatives. Studies have shown that hair dyes can leach into capillaries from the hair scalp and cause diseases, such as non-Hodgkin lymphoma and leukemia, among others (Lewis, Mama & Hawkes, 2013).
Therefore, the development of natural hair dye production methods to reduce these drawbacks has become a major market demand. This leads to our aim to synthesize natural, harmless hair dyes with engineered bacteria.
As early as 1993, various bacteria could be engineered to synthesize ancient natural pigments such as indigo. These synthesized pigments were mainly used in the industry (Murdock, Ensley, Serdar & Thalen, 1993). We believe that novel, convenient, harmless, and diverse in color methods to synthesize pigments will bring new changes to the market and introduce huge social and economic benefits.
We successfully synthesized melanin, indigo, dopaxanthin, and indoline-betacyanin and dyed hair into black, blue, and red. We used Vibrio natriegens, a faster-growing chassis organism (Tschirhart et al., 2019), to increase the rate of production. V. natriegens could produce melanin faster than E. coli. To prove that this concept works in the real world, we successfully dyed hair with the synthesized pigments.
Synthetic hair dyes in the market utilize the combination of the oxidant, hydrogen peroxide, and pigment precursors (Lewis et al., 2013). We propose using laccase, an oxidase, and natural pigment precursors to replace this method (Jeon et al., 2010). We successfully produced and extracted laccase, performed an activity assay, and acquired positive results. We plan to combine the enzyme with pigment precursors and try dying hair with the novel combination. We will also try to optimize the dyeing protocols and discuss the safety aspects of potential products.
1. Lewis, D., Mama, J., & Hawkes, J. (2013). A Review of Aspects of Oxidative Hair Dye Chemistry with Special Reference to N-Nitrosamine Formation. Materials, 6(2), 517-534. doi: 10.3390/ma6020517
2. Murdock, D., Ensley, B. D., Serdar, C., & Thalen, M. (1993). Construction of metabolic operons catalyzing the de novo biosynthesis of indigo in Escherichia coli. Bio/Technology, 11(3), 381.
3. Tschirhart, T., Shukla, V., Kelly, E., Schultzhaus, Z., NewRingeisen, E., & Erickson, J. et al. (2019). Synthetic Biology Tools for the Fast-Growing Marine Bacterium Vibrio natriegens. ACS Synthetic Biology, 8(9), 2069-2079. doi: 10.1021/acssynbio.9b00176
4. Jeon, J., Kim, E., Murugesan, K., Park, H., Kim, Y., & Kwon, J. et al. (2010). Laccase-catalysed polymeric dye synthesis from plant-derived phenols for potential application in hair dyeing: Enzymatic colourations driven by homo- or hetero-polymer synthesis. Microbial Biotechnology, 3(3), 324-335. doi: 10.1111/j.1751-7915.2009.00153.x