This New Space Sunscreen Could Protect Astronauts From Radiation!
For astronauts preparing to spend a long summer vacation on Mars, hats and umbrellas may not be enough to protect them from the harsh rays of the sun.
Just as beachgoers wear sunscreen, explorers on the Moon or Mars can one day protect themselves by using creams containing a new bioengineering material called selenomelanine, created by enriching the natural pigment melanin with metal selenium.
According to NASA, outside of Earth’s protective magnetic field, humans are exposed to many types of hazardous radiation. This includes harmful ultraviolet radiation from the sun, X-rays, and gamma rays, as well as superfast subatomic particles called galactic cosmic rays originating from outside our solar system.
Protection against the sun’s ultraviolet light
The invisible accumulation of DNA breakage caused by these space rays can lead to cancer and high doses of radiation poisoning and death. Traditional countermeasures such as lead or water shield tend to be heavy and greatly increase the cost of a space mission.
Enter melanin, a broad class of naturally occurring pigments found in animals, plants, fungi, and bacteria. Some types of melanin provide people with a wide variety of skin, hair, and eyeshades and help protect us against the sun’s ultraviolet light.
“Melanin is ubiquitous and uncanny,” “We don’t fully understand it,” NathanGianneschi, a biochemist at Northwestern University in Evanston, Illinois, told Live Science.
According to a 2014 article published in the New Journal of Science, animal melanins are divided into two main forms: eumelanin and phaeomelanin.
Eumelanin is responsible for imparting black or dark brown colors like skin and hair, while pheomelanin contains sulfur and tends to be reddish or yellowish and is found in red or auburn hair and human lips.
Pheomelanin also absorbs X-rays much more efficiently than eumelanin. Knowing this, Gianneschi and his colleagues took some pheomelanin from red rooster feathers and tried to figure out if they could make it even more protective.
Instead of sulfur, the researchers replaced the element selenium, which is located just below sulfur in the periodic table of element names and is known to play a role in preventing cancer in organisms. By doing this, they formed selenomelanine never before seen in nature.
During lab experiments, skin cells treated with selenomelanine managed to shed doses of X-ray radiation that could be fatal to a human. Selenomelanine was absorbed into the cells and formed what Gianneschi called “microparasols” or small shields around the nuclei of cells where DNA is stored. Gianneschi said the cells naturally acquire a brown or tanned color when they absorb selenomelanine.
Additional tests have shown that engineered bacteria that feed on selenium can produce selenomelanine, meaning the substance can be produced in space. The results were published in the Journal of the American Chemical Society on July 8.
Needs to be Tested in Space
Radamés J.B., a microbiologist who studies melanins at Johns Hopkins University in Baltimore, Maryland, and is not involved. “The authors provide a good example of how biology can inspire the design of a melanin analog, I like that,” Cordero told Live Science.
The material will need to be tested on humans and in space to see if it still provides the same protection. Other groups interested in working with Gianneschi and his team’s intercellular sunscreen are already in touch.
Gianneschi said that it is lightweight and can be produced from basic organic chemicals during a space mission, making it quite attractive. Selenomelanine can even be incorporated into clothing, such as the lining of a spacesuit, where it can work much like microparasols to provide sustained protection, he added.
He and his colleagues now wonder if the chemical they synthesized is present in nature, perhaps in fungi living in high-radiation environments.