Sunscreens and moisturizers derived from biological sources such as cyanobacteria could represent a safer alternative to current, synthetically produced cosmetics, research published in the European Journal of Phycology suggests.
Using organic matter to develop sunscreens could lessen the risk of adverse side effects, such as contact sensitivity and estrogen mimicking, and help prevent potentially harmful chemicals from entering the environment, lead author Peyman Derikvand of the University of Isfahan, Iran, and colleagues from Swansea and London, say.
The use of biological compounds has many potential advantages for the cosmetics industry, one of which is the organism’s ability to self-renew and reproduce, ensuring that supplies are sustainable. This is especially true for photosynthetic organisms that require only light energy, carbon dioxide and basic nutrients.
One group of such organisms, cyanobacteria, could have great potential as a source of cosmetic products for sunscreens and moisturizers because some of its species live in extremely arid habitats and thus produce compounds that give them the ability to cope with both high UV radiation and extreme desiccation.
These compounds include mycosporine-like amino acids (MAAs) and scytonemin, which provide strong screening protection from longwave and shortwave UV radiation respectively. Such natural photoprotectants could be good candidates as alternatives to synthetic UV filters.
In addition, extracellular polymeric substances (EPS) derived from cyanobacteria appear to be much more effective at retaining moisture than EPS from conventional moisture preserving materials, such as urea, glycerin and propylene glycol, currently used in cosmetics.
Cyanobacteria have higher photosynthetic and growth rates than more complex plants, simple nutritional requirements, and the ability to grow under closed cultivation systems that do not compete with agriculture. However, economic and sustainable production of these bio-compounds at the large scales required by the cosmetic industry is a key challenge.
“As we move into an era where we are turning to nature to replace synthetic chemicals, industry is being driven to look to natural product alternatives. Cyanobacteria, tiny photosynthetic microbes, offer new potential. One suite of compounds are synthesised to protect against damaging ultraviolet and intense sunlight. These compounds, as discussed in this review, offer many advantages over current synthetically derived sunscreens,” said author Carole Llewellyn, Associate Professor in Applied Aquatic Bioscience.
“On-going research into the intensive cultivation of photosynthetic microorganisms in photobioreactors is bringing new understanding in terms of design, operation and scale-up, and will steadily improve both the economics and feasibility of industrial production of cyanobacteria,” said Llewellyn.
Technical improvements coupled to market demand should see the increasing application of cyanobacterial metabolites in the cosmetics sector, the authors conclude.
Learn more: Cyanobacteria: the future of sunscreen?
New sunscreen encased in nanoparticles eliminates cancer-causing potential of traditional sunscreens
A research team including NIBIB-funded scientists has developed ananotechnology-based sunscreen that provides excellent protection from ultraviolet (UV) damage while eliminating a number of harmful effects of currently used sunscreens. The team encapsulated the UV-blocking compounds in bio-adhesive nanoparticles, which adhere to the skin well, but do not penetrate beyond the skin’s surface. These properties resulted in highly effective UV protection in a mouse model, without the adverse effects observed with commercial sunscreens, including penetration into the bloodstream and generation of reactive oxygen species, which can damage DNA and lead to cancer.
Commercial sunscreens use compounds that effectively filter out damaging UV light. However, there is concern that these agents have a variety of harmful effects due to penetration past the surface skin. For example, these products have been found in human breast tissue and urine and are known to disrupt the normal function of some hormones. Also, the exposure of the UV filters to light can produce toxic reactive oxygen species that are destructive to cells and tissues and can cause tumors through DNA damage.
“This work applies a novel bioengineering idea to a little known but significant health problem, adds Jessica Tucker, Ph.D., Director of the NIBIB Program in Delivery Systems and Devices for Drugs and Biologics. “While we are all familiar with the benefits of sunscreen, the potential toxicities from sunscreen due to penetration into the body and creation of DNA-damaging agents are not well known.Bioengineering sunscreen to inhibit penetration and keep any DNA-damaging compounds isolated in the nanoparticle and away from the skin is a great example of how a sophisticated technology can be used to solve a problem affecting the health of millions of people.”
Bioengineers and dermatologists at Yale University in New Haven, Connecticut combined their expertise in nanoparticle-based drug delivery and the molecular and cellular characteristics of the skin to address these potential health hazards of current commercial sunscreens. The results of their collaboration were reported in the September issue of Nature Materials.
Minute vessels filled with sunscreen
The group encapsulated a commonly used sunscreen, padimate O (PO), inside a nanoparticle (a very small molecule often used to transport drugs and other agents into the body). PO is related to the better-known sunscreen PABA.
The bioadhesive nanoparticle containing the sunscreen PO was tested on pigs for penetration into the skin. A control group of pigs received the PO alone, not encapsulated in a nanoparticle. The PO penetrated beyond the surface layers of skin where it could potentially enter the bloodstream through blood vessels that are in the deeper skin layers. However, the PO inside the nanoparticle remained on the surface of the skin and did not penetrate into deeper layers.
Because the bioadhesive nanoparticles, or BNPs are larger than skin pores it was somewhat expected that they could not enter the body by that route. However, skin is full of hair follicles that are larger than BNPs and so could be a way for migration into the body. Surprisingly, BNPs did not pass through the hair follicle openings either. Tests indicated that the adhesive properties of the BNPs caused them to stick to the skin surface, unable to move through the hair follicles.
Further testing showed that the BNPs were water resistant and remained on the skin for a day or more, yet were easily removed by towel wiping. They also disappeared in several days through natural exfoliation of the surface skin.
BNPs enhance the effect of sunscreen
An important test was whether the BNP-encapsulated sunscreen retained its UV filtering properties. The researchers used a mouse model to test whether PO blocked sunburn when encapsulated in the BNPs. The BNP formulation successfully provided the same amount of UV protection as the commercial products applied directly to the skin of the hairless mouse model. Surprisingly, this was achieved even though the BNPs carried only a fraction (5%) of the amount of commercial sunblock applied to the mice.
Finally, the encapsulated sunscreen was tested for the formation of damaging oxygen-carrying molecules known as reactive oxygen species, (ROS) when exposed to UV light. The researchers hypothesized that any ROS created by the sunscreen’s interaction with UV would stay contained inside the BNP, unable to damage surrounding tissue. Following exposure to UV light, no damaging ROS were detected outside of the nanoparticle, indicating that any harmful agents that were formed remained inside of the nanoparticle, unable to make contact with the skin.