Cosmetic Science Article Submission

Urban Defense: Strategies for Pollution Protection

By: Tia Alkazaz, Marketing Manager, Active Micro Technologies

As the number of people living in cities is increasing, there is a growing concern about the effects of atmospheric pollution on skin health. The harmful effects of ultraviolet radiation and smoking on skin health is well understood, and appropriate skin protection measures have been established to prevent premature skin aging. However, atmospheric pollution is a relatively newer concern that has the cosmetic industry developing new ingredients, and adapting formulation concepts for skin protection and repair. Air pollution in Asia is at an all-time high due to auto emissions, cigarette and industrial smoke.(1) The Environmental Protection Agency (EPA) is leading the charge against air pollution in the United States, as awareness of the skin damaging effects of pollution is spreading through the Western hemisphere. Addressing concerns over pollution allows cosmetic brands to leverage the influence of the expanded consumer awareness into a new market for skin care that works to actively fight against pollution.

The skin is our body’s largest organ, and as such, it’s constantly exposed to the fine particles, heavy metals, ozone, carbon monoxide, or volatile organic compounds that are concentrated in the air. These particles can adhere to the skin and transfer pollutants into the skin. The latest standard of pollution, the Environmental Protection Agency’s PM 2.5 (Particulate Matter 2.5, air pollutants with a diameter of 2.5 microns or less) measures tiny particles that reduce visibility and have implications in overall air quality. These finer particles disrupt the skin barrier, damage skin tissue, and accelerate aging.(2) Carbon and metal micro particles found in polluted air embed in the epidermis causing oxidative stress, initiating the inflammatory cascade that leads to the breakdown of collagen, elastin, and other structural components in the skin. Additionally, skin exposure to carbon micro particles can overstimulate keratinocytes and melanocytes, resulting in hyper-pigmentation and age spots.(3)

While acting as a natural shield, our skin is limited in its ability to defend against today’s prevailing environmental stressors. Major anti-pollution claims for cosmetics emphasize film forming, anti-oxidant, and anti-inflammatory capabilities. Protecting the skin from atmospheric pollution is now a target for cosmetic ingredient suppliers, and several strategies are available for skin defense. These strategies address pollution, not only on the surface of the skin, but also deeper at the cellular level.
One effective way to defend against atmospheric pollution is isolating the skin from external environmental factors with by forming a film on the skin surface. Providing a physical barrier against environmental pollutants is currently done through the use of silicones, peptides, and polysaccharide rich systems.

Silicone film formers can improve the aesthetics of formulations and reduce the detrimental impact of environmental pollution by inhibiting the adhesion of particulate matter on the skin surface. Silicone based film forming technology, such as dimethicone, cyclopentasiloxane, or cyclohexasiloxane, can form a flexible film on the surface of the skin and shield the skin from environmental pollution due to silicone’s ability to form low surface energy coatings. Silicones are able to create a protective sheath that improves the softness and smoothness of skin, however after several applications, silicones may leave a heavy, waxy buildup on the skin that consumers find unpleasant.
As an alternative to silicones, peptides or polysaccharide rich systems can be used to shield the surface of the skin. Naturally derived peptides, such as those in Glycerin and Moringa Pterygosperma Seed Extract, are also able to provide pollution protection via film forming. Peptides obtained by theextraction of the seeds of Moringa pterygosperma are able to form a barrier on the surface of the skinto facilitate the removal of environmental particulates that adhere to the skin, protecting skin againstaggressions by pollutants.

Polysaccharide rich systems, such as those found in Selaginella lepidophylla extract, are able to inhibitatmospheric particulates from remaining on, or penetrating into, the skin by creating a syntheticscaffolding. Selaginella lepidophylla, commonly known as the Rose of Jericho, is a desert botanical ableto withstand long periods of almost total desiccation and then fully recover when exposed to elevatedmoisture levels. Exposure to oxidative stress triggers the production of the plant’s moisture-retentivesystem that is rich in polysaccharides. Those polysaccharides help retain water, keeping Selaginellalepidophylla hydrated throughout droughts, preventing desiccation. The protective and moistureretentiveproperties associated with the plant’s polysaccharides and secondary metabolites enableformulators to create functional products that deliver film forming benefits to the skin.

Each of these polysaccharide rich systems, peptides, and silicones provide a physical barrier that prevents embedment of carbon particles, thus reducing the signs of extrinsic aging. Performing aPollution Protection Analysis will determine the effectiveness of a physical barrier provided by a filmforming ingredient against micronized charcoal using the EPA’s PM 2.5 standard. The application of the film forming ingredient to the volar forearm followed by contamination with a premeasured amount ofmicronized charcoal and subsequent washing with a controlled amount of water allows for theassessment of the film-former’s ability to inhibit pollution remaining on the skin. Images of the skintaken pre- and post-wash using a dissecting microscope undergo color analysis and the results aredepicted in optical density values and pigmentation histograms. This allows pollution protection to bemeasured quantitatively. The lower the mean optical density value the better protection against carbonparticle embedment or PM 2.5 inhibition. A physical barrier established by a film-former can effectivelyprevent the deposition of invasive PM 2.5 particles into the skin’s fine lines and wrinkles, thereforedefending the skin against pollution-driven aging.

Addressing pollution at a cellular level represents a revolutionary shift, as typical anti-pollution productsfocus on the skin surface. Strategies to defend against cellular pollution include addressing free radicaldamage through the topical application of an antioxidant, as well as addressing oxidative stress byupregulating cellular antioxidants.

Environmental pollutants increase the number of free radicals in the air and these free radicals canaccumulate and disrupt normal cellular functions, resulting in premature skin aging. Vitamin C (ascorbicacid) and Vitamin E are antioxidants capable of neutralizing free radicals to protect cells against the effects of environmental pollution. Vitamin C is water soluble and Vitamin E is lipid soluble, so the combination of the two can protect against free radical damage of both the hydrophilic and lipophiliccompartments of the cell. Regular application of cosmetics rich in Vitamin C and Vitamin E can be one of the most effective ways to neutralize free radicals and strengthen the skin’s defense against environmental particulates.

Instead of topically applying an antioxidant to defend against free radical damage, understanding sulfur biology has allowed for a method of enhancing cellular antioxidant activity to provide pollution protection from within. Environmental pollutants are able to reduce the levels of cellular antioxidants which act as the main line of defense against cellular oxidative damage.(3) Understanding the pathways leading to the induction of antioxidant responses, will enable chemists to develop strategies that protect against oxidative damage. The Mitochondrial Free Radical Theory of Aging is a widely accepted theory which explains the cause of skin aging.(4) This theory depicts oxidative stress as a byproduct of cellular metabolism, explaining that overproduction of reactive oxygen species pushes the capacity of mitochondrial antioxidant defenses, causing a buildup of oxidative damage to occur.(4) Accumulation of reactive oxygen species in the mitochondria causes cellular dysfunction, resulting in changes to our skin’s appearance – including the visible signs of aging like fine lines and wrinkles.

Sulfur biology is a relatively untapped method for controlling mitochondrial activity, presenting real opportunity for brand defining anti-aging claims. Sulfated polysaccharides derived from dinoflagellate microalgae, such as Crypthecodinium cohnii, have the ability to combat of aging via upregulation of cellular glutathione. Glutathione is a low molecular weight, thiol-bearing, free-radical scavenger that decreases within the epidermis of aged and damaged skin. The simple, topical application of glutathione is ineffective. Topical application does not allow for an increase of cellular glutathione levels, as the zwitterionic structure of the molecule hinders its ability to penetrate through the lipophilic barriers of the stratum corneum and cell membranes. Sulfated polysaccharides, isolated from dinoflagellate microalgae, act as sulfide donors and play a role in the upregulation of cellular glutathione. By restoring levels of depleted glutathione, resulting from contamination of atmospheric particulates, purification of pollutants occurs at a cellular level. Elevated levels of glutathione in the cell also help combat inflammation, preserve overall cell health, and slow the signs and symptoms of aging. Increasing glutathione levels can help convert oxidized molecules back to their reduced state and prevent cell damage.(5)

Whether the approach is on the surface of the skin or at a cellular level, anti-aging products will always be highly desired in the cosmetic industry. The rapidly growing interest in pollution protection formulations is sure to be well-received by appearance minded consumers. Whether defense comes from a physical barrier by a film forming ingredient or upregulating cellular antioxidant levels, providing cosmetic solutions that are able to preserve skin health during exposure to environmental stressors represents a high potential area of innovation for brands to explore.

REFERENCES
(1) A. Vierkotter, T. Schilkowski, U. Ranft, D. Sugiri, M. Matsui, U. Kramer, J. Krutmann, Airborne particle exposure and extrinsic aging, Journal of Investigative Dermatology, 130, 2719-2716 (2010). http://www.sciencedirect.com/science/article/pii/S0022202X15346455
(2) N. Puizina-Ivic, Skin aging, Acta Dermatoven, 17, 47-54 (2008). http://dr-baumann.co.uk/science/Skin%20Aging.pdf
(3) B. Poljsak, R. Dahmane, Free radicals and extrinsic skin aging, Dermatology Research and Practice, 3, 135-206 (2012). http://www.hindawi.com/journals/drp/2012/135206/abs/
(4) B. Poljsak, R. Dahmane, A. Godic, Intrinsic skin aging: the role of oxidative stress, Acta Dermatoven, 21, 33-36 (2012).
https://www.researchgate.net/profile/Aleksandar_Godic/publication/232062534_Intrinsic_skin_aging_The_role_of_oxidative_stress/links/0912f512645925d9cd000000.pdf
(5) J. Limon-Pacheco, M. Gonsebatt, The role of antioxidants and antioxidant related enzymes in proactive responses to environmentally induced oxidative stress, Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 674, 137-147 (2009). http://www.sciencedirect.com/science/article/pii/S1383571808002714

 

Evolution of Bleach Protection

By: Hillary A. Phillis, Marketing Manager, Active Concepts LLC

 

Introduction

Identity or Accessory?  Lucinda Ellery, hair specialist, wrote a feature article for The Huffington Post explaining that we view our hair as a “reflection of our identity.”1 But truly, our hair is both an accessory and part of our identity. It is simultaneously personal and public.  Beauty, along with liberation and femininity, are social movements that track parallel to the trends in the hair care industry.  Hair styles, and colors, are symbolic and iconic statements made throughout history.

In the quest for individual expression, hair is exposed to mechanical, thermal, and chemical stressors. Mechanical and thermal processes contribute to some hair damage.  However, chemical treatments tend to push hair fibers to their limit. An impressive 75% of women color their hair and a growing percentage of men.2 Blonde is the most coveted hair color giving bleach the strong hold on the market. Recent color hair trends reveal that vibrant magentas, pastel pinks, punchy purples, and lovely lavenders are dominating the media.  The only way to achieve these new, popular hair colors is by first bleaching the hair, and then applying your color of desire. Imagine the damage!  Fortunately, technological advances in cosmetic chemistry have allowed for the creation of innovative products that are able to form a scaffolding around the hair shaft, protecting the hair during chemical processing.

Structure of hair

The hair fiber consists of three main layers: medulla, cortex, and cuticle. The innermost layer, the medulla, is a thin core of transparent cells and air spaces. In some humans, the medulla has a distinct shape within the core of hair that can only be seen using highly magnified viewing methods. The cortex is the main body of the hair fiber and sits between the medulla and the cuticle. The cortex consists of long keratin filaments held together via disulfide and hydrogen bonds, where the melanin pigment is found. The cuticle, or outermost layer of the hair, protects the cortex and medulla. This protective layer is composed of overlapping, tightly packed, downward-facing scales. When in this position, the cuticle prevents moisture loss, while acting as the fiber’s protective barrier.

All three layers comprise the shaft of the hair, the non-living portion that extends from the scalp, with the main constituent being the protein keratin. The keratin protein is compacted and cemented together to give a distinct shape to the hair strand. Keratin, by nature, is a sulfur-rich protein with strong disulfide bonds producing hair’s resilience and strength. The hair shaft is strengthened by hydrogen bonds which are weaker, yet more numerous than disulfide bonds, and contribute to hair’s flexibility.

The medulla and cortex contains the pigments known as melanin, specifically eumelanin and pheomelanin. Melanin is responsible for giving skin, eyes, and hair visible pigment. Eumelanin is responsible for dark brown shades while pheomelanin produces red pigmentation. Pigment ratios, or lack thereof, produce different shades of hair color. Complete loss of melanin produces white or gray hues, while low concentrations of both proteins result in naturally blonde hair. In order to alter the color of hair, the melanin within the hair fiber must be altered.

Bleaching Process

Bleach is used to lighten locks to create the perfect creamy, platinum hue, or to prep the hair for additional color treatments. Volumes of hydrogen peroxide ranging from ten to forty are used as developer in the bleaching process to deliver a range of desired results. Each volume has a specific hydrogen peroxide content ranging from 3% to 12%. The higher the volume the more oxygen that can be released in the hair shaft when applied. Therefore, the volume is selected specifically for the treatment or lift desired. The volume of hydrogen peroxide, also known as the developer, is added into the bleach powder or cream. The bleach powder or cream typically contain agents to speed up the process of bleaching the hair such as: ammonium persulfate, potassium persulfate, sodium persulfate, or a mixture of all three. The highly alkaline mixture of developer and bleach raises the cuticle of the hair fiber and allows hydrogen peroxide to penetrate the cortex, acting as the oxidizing agent. A series of irreversible oxidation reactions utilizing oxygen remove electrons from the melanin resulting in the well-known color change.

The melanin within the cortex remains present, but is rendered colorless through the reactions, producing the resulting blonde palette. The lighter or more lifted the hair, the more visible the pale yellow tint of keratin.

Hair is naturally proteinaceous containing a vast amount of oxidizable groups, not just melanin. When bleaching the hair, more than one type of bond and protein is affected, resulting in damaged, weakened hair. Hydrogen peroxide damages thioester bonds between cuticle cells, areas rich in amino acids, ionic bonds, and disulfide bonds in the cortical matrix. But the damage doesn’t stop there, 18-methyl eicosanoic acid, a fatty acid found on the surface of the hair is degraded resulting in dry, brittle hair fibers.  Additionally, during the chemical process the cuticle is raised, causing it to be porous, like a sponge. Just as sponges behave, the hair soaks up water quickly but it loses it just as fast. In conjunction with stressors, fibers receive no relief from the damage imposed.

As popular trends continue toward the extreme, repairing the structure and elasticity, particularly after bleach applications, is not only desired, but necessary.

Damage Prevention & Repair

The degree of damage inflicted during chemical processes rarely deters a consumer. Repair is often the afterthought resulting from chemical damage, when the excitement has worn off.

Throughout the evolution of modern hair care, consumers have witnessed multiple iterations of hair repair options. Typical means of damage repair include; reparative shampoos, deep or leave in conditioners, treatments, hair masks, and most recently, hair oils. These current market offerings utilize a range of mechanisms, which stand on their predecessors to target both pre and post treatment repair.

Dating back to the early 1970’s, dimer acid esters were used as a pre-treatment or applied with the bleach to provide an additional layer of protection from the harsh chemical treatment.3  According to US Patent 4,067,345 Kelly, et al. hair treated with this protective organic compound was less susceptible to post bleach damage. Meanwhile, silicones gained popularity in the 70’s, offering a multitude of varieties that have been and are still largely utilized in hair care.  US Patent 8,740,995 Schweinsberg, et al. specifically discusses the pretreatment use of a 4-morpholinomethyl-substituted silicone which offers improved hair protection with no negative effect on the outcome of the oxidative treatment.4  Silicones and synthetic copolymers characteristic barrier protection continues to be the main driving force in pre-bleach treatments.

Post-treatment repair offerings have also spanned the spectrum over the years. US Patent 5,136,093 Smith discusses quaternized panthenol as a remedy for post-bleached fibers in the early 90’s via hair fiber penetration. Quaternized panthenol was claimed to penetrate the hair deeply to provide long lasting moisture control, reduce split ends, smooth the cuticle, and repair damage by chemical processes.5 Post-treatment remedies typically take advantage of the damaged, ruptured cuticle to offer short term smoothing. US Patent 8,927,751 Moriya utilizes an organopolysiloxane with a specific organic group to smooth the cuticle and deliver enhanced combability properties to the damaged hair.6 Additional mechanisms range from utilizing silicones, silicone copolymers, and silicone moieties to coat and protect from further damage, quaternary ammonia compounds to condition and rehydrate, and hydrolyzed proteins to strengthen and protect damaged locks. Anionic keratin sulfonates have also been used to condition and strengthen the hair by binding to the fiber post chemical treatment. Post-treatment mechanisms have evolved to a more recent technology: bond repair. US Patent 9,095,518 Pressly, et al. discusses the repair of the ruptured disulfide bonds within the hair. US Patent 9,326,926 Pressly, et al. utilizes polyfunctional compounds capable of forming ionic bonds to aid in repair to bring hair back to its pretreatment state.7,8 Evolution of both pre and post treatments have resulted in a traceable timeline of innovation from dimer acid esters, silicone based mechanisms, to bond repair.

The personal care industry often seeks information from a multitude of other industries and vice versa. Currently within the chemical industry the pressure for greener product chemistry and the push to move away from petrochemicals and silicone based technologies has impacted the lines of innovation within the personal care raw materials industry. Just as the timeline of evolution is visible through bleach repair, the shift to accommodate consumer pressures will become evident in the coming years. As the market demands new, multifunctional mechanisms innovation must shift to accommodate.

Leading edge technology indicates that mimicking bio-films formed by microorganisms could be the next step in chemical process protection. Synthetic biology is the re-design of existing, natural biological systems for other, useful purposes.9 Through synthetic biology inspiration for natural product chemistry can be drawn. Specifically, bio-films, unlike typical films, are polymeric chains forming a conglomeration of proteins, amino acids and polysaccharides that creates a complex, supportive interwoven matrix. A potential mechanism, US Patent Application 62/289,493, mimics the structure of bio-films, creating a supporting scaffolding matrix on the hair fiber while still allowing the bleach particles to penetrate the cortex and react. Innovative research, inspired by nature shows a supportive scaffolding matrix, derived from hydrolyzed pea protein & Selaginella lepidophylla extract, is a chemically resilient material that ionically binds to the hair’s cuticle offering long-term protection from harsh hair color, free radicals, peroxides, and environmental stressors.

The three dimensional structure self-situates between the cuticle and the cortex where it self assembles to its supporting scaffolding with a semi-permeable membrane to reinforce and support the hair’s structure. This support allows for minimal damage to the fiber during the harsh chemical process. Concurrently, the product seals the cuticle to lock in moisture and prevent further damage. The concept of prevention via support with simultaneous long term sealing of the cuticle is the leading edge of next generation hair care.

In a world where more is more, combining prevention and repair is the next logical step to allow trends like bright purple locks to become attainable without the excess damage. An engineered plant-based hybrid biopolymer utilizing poly-compound reactions brings the idea of a multi-step and multi-level web of protection to life in the next iteration of consumer inspired hair care technology.

References:
1-   Ellery, Lucinda. Hair and History: Why Hair is Important to Women. Huffington Post. 07 Sept 2014. Web. 20 June 2016.
2-   Sherrow V. Encyclopedia of Hair: A Cultural History. Westport, CT: Greenwood Press;2006.
3-   Kelly et al. US Patent 4,067,345, 1970
4-   Schweinsberg. US Patent 8,740,995, 2013
5-   Smith. US Patent 5,136,093, 1991
6-   Moriya. US Patent 8,927,751, 2011
7-   Pressly et al. US Patent 9,095,518, 2012
8-   Pressly et al. US Patent 9,326,926, 2014
9-   Synthetic Biology. Web. 25 July 2016