Pharaoh Akhenaten worshiping Aten
(The Sun Disc)
The sun has been revered & celebrated since ancient civilisations for its ability to give life & energy. Some cultures, including ancient Egyptians, Romans & Native Americans, even worshipped the sun as a deity. For as long as they have celebrated the sun, however, humans have also respected & protected themselves from it.
While over the counter sunscreens are an invention of the twentieth century, sun protection is not. Throughout history, fair skin has been associated with beauty & high societal standing, while a tan was associated with working class. It wasn’t until after the Industrial Revolution that it began to be indicative of one’s ability to escape cities & travel for leisure.
The cultural craze for tanning is largely attributed to Coco Channel, who in 1923 fell asleep while on a Mediterranean cruise & set a new beauty trend when she disembarked sunburnt in Cannes. So, while the first report that sunburn in human skin is caused by UV radiation, specifically wavelengths in the UVB range (280–315 nm) was made in 1922 by Germans Karl Hausser & Wilhelm Vahle, people did not take the threat seriously preferring the “wealthy & healthy” look a tan would afford them.
Through the decades, people’s relationship to the sun & tanning has changed. The 60s & 70s saw a rise in tanning, especially with the appearance of tanning beds in the late 70s. By the 80s & 90s, the threat of the sun’s radiation began to be taken more seriously with advances in sunscreen technologies. With the continuous rise in awareness in the last decades of the effect of UV exposure on skin cancer incidents, a new attitude to tanning is developing again, with the focus moving towards protection.
ANCIENT SUN PROTECTION
Studying ancient art & literature, it was easy to see the importance the sun played in society. However, there were also clear depictions of forms of sun protection, from protective clothing to plant extracts. Ancient Greeks, for example, were known to use olive oil as protection from the sun & there were many instances in their literature, like in Homer’s Odyssey, where protective clothing was worn. Ancient Egyptians are credited with creating the first sunscreen, formulating salves specifically to curb the sun’s harmful effect. Their sunscreens were based on extracts of rice, jasmine, lupine plants & aloe vera & used powdered particulates from clay & calcite.
20th CENTURY SUNSCREENS
Synthetic sunscreens were first developed in 1928 & were emulsions of the two chemicals benzyl salicylate & benzyl cinnamate. After the patenting of para-aminobenzoic acid (PABA) as a UVB absorber in 1943, companies moved on to using para-amino benzoates as the active ingredients in sunscreens.
Australian chemist Milton Blake is credited with being the first to experiment with sun protection, creating a sun cream that was produced & sold in the 1930s, by Hamilton Laboratories. The first major commercial sunscreen product on the cosmetics market, however, came in 1936 from chemist, & L’Oreal founder, Eugene Schueller, under the name ‘Ambre Solaire’. Neither of these two formulations were particularly effective as sun protection.
Advertisement for Ambre Solaire by L’Oreal
The first commercially viable sun protection cream is often attributed to Austrian chemist Franz Greiter for his Gletscher Crème, introduced in 1938. His formulation is believed to have had a sun protection factor (SPF) of 2 & was the basis for the company Piz Buin, named after the mountain Greiter allegedly got sunburnt on, inspiring his work in the field of sun protection.
Piz Buin is still a successful marketer of sunscreen today. Greiter contributed greatly to the developments of the sunscreen industry. He was the first to develop sunscreens that absorb both UVA & UVB sun rays & developed water-resistant products. One of his biggest contributions, however, may be the introduction of the concept of SPF in 1962, which has become the global standard for measuring the effectiveness of sunscreen protection against UVB rays.
In the 1940s, Benjamin Green, a pharmacist & US Air Force member from Florida, invented Red Vet Pet (red veterinary petroleum) for the US military. A red petroleum-based jelly-like substance, Red Vet Pet formed a successful barrier against UV radiation for WWII veterans but with its sticky & uncomfortable feel & its penchant for staining clothing, it did not outlive the war. Instead, in 1944 he patented his formulation & refined it by mixing it with cocoa butter & coconut oil to create a product that would form the basis for Coppertone suntan cream, the first commercially mass-produced sunscreen in the US.
By the 1970s the market shifted towards sun protection, claiming to allow people to tan without burning. This was developing into big business, with several companies maximising profits with advances in sunscreen technology. SPF ratings rose from the lowly factors of 4 or 8 to maximums of SPF 15 Piz Buin introduced UVA & UVB filters, & the first water-resistant sunscreens were introduced. This increase in popularity saw the beginning of various regulations coming in to play. The US Food & Drug Administration (FDA) proposed standards for safety & efficacy of sunscreens in 1978, mostly focusing on the requirement for SPF testing & the proper labelling of SPF on product labels.
Research into UV radiation really picked up in the 1980s, with the importance & impact of UVA radiation, along with UVB, in skin cancer gaining attention. The first UVA/UVB sunscreen to be commercialised was by Coppertone in 1985, who also created the first sweat-proof sunscreen for athletes.
With the increased risk associated to UVA radiation, the chemical filter avobenzone, the only UVA-specific filter on the market at the time, became more popular in sunscreen formulations & was approved by the FDA in 1988. With its bright colours, the 80s also created a market for zinc oxide to be used in sunscreens. Sunblocks containing zinc oxide were coloured yellow, lavender, light blue & turquoise to match swimwear.
Original Coppertone Girl ad released in 1953
Sunscreen technology continued to develop in the 1990s with new formulations such as sprays & gels being developed. While avobenzone is an effective UVA filter, it has a low photostability, so it was combined with other chemicals to stabilise it. Sunscreen producers in the US were allowed to market their products as offering UVA protection by containing avobenzone since 1997 according to FDA regulations. Research in the 90s also focused on new UVA filters such as micronized zinc oxide (ZnO) & titanium dioxide (TiO2).
MODERN SUN PROTECTION
With the turn of the century, low SPF sunscreens were replaced by those with higher protection factors. By 2009, only 6 percent of sunscreens had SPF levels below 5. SPF also started to make its way into everyday skincare & make-up products such as moisturising creams, foundations & lip balms.
It is now accepted that the longer wavelengths & more penetrating UVA rays are the most harmful UV rays from the sun as the predominant causes for skin cancer. So more & more focus has been put on creating broad-spectrum sunscreens that can effectively protect against both the skin cancer causing UVA & the sun-burning & ageing UVB rays.
Cricketer Umar Akmal with traditional ZnO sunscreen on his face
Many of the classic UV filters have also been coming under scrutiny in recent years. Through the years, UV filters have predominantly been chemical filters that absorb & dissipate UV rays. Two specific chemical filters, oxybenzone & octinoxate, are coming under fire for their pollution of the environment, specifically their effects on coral.
In 2018, Hawaii implemented the world’s first ban on chemical sunscreens containing the chemicals oxybenzone & octinoxate, to come into effect on January 1, 2021.
Mineral UV filters, ZnO & TiO2, form a physical barrier on the skin that deflects & scatters UV rays. Mineral sunscreens are becoming increasingly more popular as they offer more extensive broad-spectrum protection, have higher photostability & lower instances of allergic reactions than chemical sunscreens.
ZnO is a globally approved natural mineral ingredient, considered the most effective UV filter in broad-spectrum sunscreen, providing extensive protection against both UVA & UVB rays. Micronised & nanoparticle mineral filters were developed in the 21st century in order to overcome the unpleasant thickness & white cast associated with traditional mineral UV filters.
CURRENT ZnO FORMS
Mineral sunscreens with ZnO as a UV filter currently on the market contain ZnO in one of two forms; micron formulations, with particles in the 2 to 10 µm size range, or nano formulations, with particles in the 10 to 40 nm range. Each formulation has its benefits & disadvantages. The larger particle size of micron formulations confers a better health & safety profile, however, the smaller nano ZnO particles are more effective sunscreens so are often preferred by formulators.
Conventional ZnO forms Micron Vs Nano
Assuming no uncontrolled agglomeration takes place, nano ZnO provides a higher protection to UV rays per percentage mass & can cover a higher surface area per percentage mass than micron ZnO, making it a more effective sunscreen additive. It also forms a more visually & aesthetically pleasing sunscreen since it has a high level of transparency & smaller particle size. However, both nano & micron ZnO exhibit uncontrolled agglomeration which negatively impacts these properties.
Micron ZnO is considered to be the safer option compared to nano ZnO, due to its larger particle size. The small particles in the nano form may be highly toxic to humans & highly phytotoxic as they are suspected to penetrate through human skin & accumulate in the roots of plants. Micron ZnO also has an advantage over nano ZnO in that it offers more effective protection against high energy visible light & blue light.
THE FUTURE OF SUNSCREEN
Much progress has been made in both the effectiveness & the aesthetic properties of sunscreens through the years. Consumers, however, are getting increasingly savvier & involved in the sourcing & health & environmental benefits of the ingredients in their products. So, while they demand effective sunscreen products, that are pleasant to wear, they also want to ensure they are safe both for their own health & the environment. With these criteria in mind, the future of sunscreen seems to be in simpler formulations with less chemical additives & more natural, organic or vegan ingredients.
As broad-spectrum protection against UVA & UVB radiation is widely accepted as a necessity in the current sunscreen market, research is now moving on to added benefits & protections that can be offered from sunscreen additives. In 2006, UK researcher Rachel Haywood, first provided evidence that visible light (400–700 nm) also contributes to skin damage, opening the door for sunscreen additives that can protect against high energy visible light & blue light as well as UV radiation.
THE FUTURE IS NOW – MicNo®
Entekno Materials have designed & developed innovative MicNo® ZnO Particle Technology; a mineral UV filter to offer sunscreen formulators a single additive to provide broad-spectrum protection while overcoming the disadvantages of both micron & nano ZnO. MicNo® is a tailored, platelet-shaped, micron-sized particle composed of nano primary particles. The uniquely designed morphology of MicNo particles enables them to behave as safe micron particles over the skin & as transparent nano particles under the light.
MicNo® is a more effective UV filter to both micron & nano ZnO, offering a much higher UV protection per percentage mass & a much higher absorbance of rays within the UV wavelength, especially in the UVA range. MicNo® also offers a higher SPF & has exhibited a higher visible light transparency when used at the same concentration as commercial transparent nano ZnO. MicNo® has also been shown to provide high protection against high energy visible light & blue light.
The superior covering ability of MicNo® compared to conventional ZnO, enables formulators to use less UV filter to achieve efficient, cost-effective, high SPF formulations. Its novel hexagonal shape allows it to cover approximately 70% more surface area mass than the same amount of nano ZnO, assuming no agglomeration takes place. Another advantage of MicNo® over the commercially available versions of ZnO is that it exhibits low levels of uncontrolled agglomeration, as opposed to both micron & nano ZnO.
Distribution of 80 nano ZnO particles compared to MicNo®
MicNo® has exhibited a higher visible light transparency than the current commercial nano ZnO particles. It can achieve a high transparency percentage at 440 nm wavelength meaning the traditional white cast effect associated with ZnO is reduced. It also has excellent dispersion properties, allowing for a smooth application & feeling on the skin.
MicNo® is not only an unparalleled UV filter, but it is also a much safer option to commercially available nano ZnO. The particle size in MicNo® means it does not accumulate in plant roots or permeate the skin’s epidermis. Research has shown that MicNo® presents much less cytotoxicity, genotoxicity & phototoxicity making it more biocompatible & safer when compared to commercial nano ZnO. This biocompatibility of MicNo® makes it a much kinder sunscreen for the environment as it causes less pollution & damage to marine & plant life. As a natural, mineral ingredient MicNo® has received the COSMOS Approved Raw material & ECOCERT Natural accreditations.
PRESERVATIVE FREE FORMULATIONS IN THE FUTURE?
Possibly, since MicNo® excels with its antimicrobial properties, allowing for simpler formulations requiring less or no preservatives. MicNo® has exhibited broad-spectrum antibacterial activity against a range of micro-organisms & a number of fungi. The need for fewer preservatives would mean less risks of adverse reactions & a decrease in total number of ingredients needed for a final formulation, which could translate to lower formulation costs.
If you are looking for a single sunscreen additive to provide superior broad-spectrum UV protection while remaining safe for humans & the environment, look no further than MicNo®. MicNo® offers a cost-effective opportunity for a competitive formulation that meets the current requirements of the modern consumer & also prepares for their future demands.
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