Nav: Home

New biomaterial could shield against harmful radiation

July 08, 2020

EVANSTON, Ill.-- Packing for outer space? Here's one thing you won't want to forget.

Northwestern University researchers have synthesized a new form of melanin enriched with selenium. Called selenomelanin, this new biomaterial shows extraordinary promise as a shield for human tissue against harmful radiation.

"Given the increased interest in space travel, and the general need for lightweight, multifunctional and radioprotective biomaterials, we've become excited about the potential of melanin," said Northwestern's Nathan Gianneschi, who led the research. "It occurred to our postdoctoral fellow Wei Cao that melanin containing selenium would offer better protection than other forms of melanin. That brought up the intriguing possibility that this as-yet undiscovered melanin may very well exist in nature, being used in this way. So we skipped the discovery part and decided to make it ourselves."

The research will be published online on Wednesday, July 8 in the Journal of the American Chemical Society, ahead of publication in the July print edition.

Gianneschi is the Jacob and Rosalind Cohn Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences and associate director of the International Institute for Nanotechnology. Cao is the paper's first author.

Melanin is found in most organisms across the plant and animal kingdoms, as well as in bacteria and fungi. Though best known for pigmentation, melanin also provides valuable protection from radiation. Five kinds of melanin have been observed in nature, with pheomelanin (the pigment in red hair) shown to absorb X-rays more efficiently than the more common eumelanin (black and brown pigments in dark hair).

Unwanted exposure to radiation occurs during many common activities, from air travel to X-ray diagnosis and clinical radiation therapy. It's an even greater consideration in extreme cases like a nuclear reactor malfunction or human space travel. NASA's landmark "Twins Study" showed damage to astronaut Scott Kelly's DNA from his year in orbit. An astronaut on a Mars mission could receive up to 700 times more radiation than on Earth.

Compared to the weight and bulk of traditional radioprotective materials like lead, melanin it is lighter and more flexible in how it can be used. Melanin samples are currently in orbit at the International Space Station, being studied by another research team for the material's response to radiation exposure. Recent studies have focused on pheomelanin, which contains sulfur, as the best candidate for that purpose.

Gianneschi's team hypothesized, however, that a new kind of melanin -- enriched with selenium instead of sulfur -- would provide better protection against X-rays. Selenium is an essential micronutrient that plays an important role in cancer prevention, and previous research reports that selenium compounds can protect animals against radiation. These compounds are found in normal human proteins, but have not been associated with melanin in nature before.

Gianneschi's team synthesized the new biomaterial, which they called "selenomelanin," and used it to treat living cells. For comparison, they also prepared cells treated with synthetic pheomelanin and eumelanin, as well as cells with no protective melanin.

After receiving a dose of radiation that would be lethal to a human being, only the cells treated with selenomelanin still exhibited a normal cell cycle.

"Our results demonstrated that selenomelanin offers superior protection from radiation," Gianneschi said. "We also found that it was easier to synthesize selenomelanin than pheomelanin, and what we created was closer than synthetic pheomelanin to the melanin found in nature."

Further testing with bacteria showed that selenomelanin can be biosynthesized, meaning that live cells fed with appropriate nutrients can then produce selenomelanin on their own -- and retain its radioprotective properties. In fact, although the researchers synthesized selenomelanin in their lab, they believe it may already be present in nature.

"With an abundant source of selenium in the environment, some organisms may have been able to adapt to extreme circumstances such radiation through the beneficial effects of selenomelanin," Gianneschi said.

"Our work points to the possibility that melanin may act as a repository for selenium, helping ensure that organisms benefit from it," said Cao. "Selenomelanin may play an important role in how selenium is metabolized and distributed biologically. It's an area for further investigation."

Gianneschi and his team envision that this new biomaterial could be applied to a person's skin, like a melanin-based sunscreen. It could also be used as a protective film to shield materials from radiation while in transit.
-end-
Gianneschi also is a professor of biomedical engineering and materials science and engineering in the McCormick School of Engineering and a member of the Chemistry of Life Processes Institute, Simpson Querrey Institute and Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

The study, "Selenomelanin: An abiotic selenium analogue of pheomelanin," was supported by the Air Force Office of Scientific Research through a MURI Grant (FA9550-18-1-0142) and a supplemental grant (AFOSR FA9550-18-1-0477). The MURI collaboration included Michael D. Burkart from the University of California San Diego, Matthew D. Shawkey from the University of Ghent and Ali Dhinojwala from the University of Akron, as well as Zheng Wang from the U.S. Navy and Michael R. Wasielewski from Northwestern.

Northwestern University

Related Radiation Articles:

What membrane can do in dealing with radiation
USTC recently found that polymethylmethacrylate (PMMA) and polyvinyl chloride (PVC) can release acidic substance under γ radiation, whose amount is proportional to the radiation intensity.
First measurements of radiation levels on the moon
In the current issue (25 September) of the prestigious journal Science Advances, Chinese and German scientists report for the first time on time-resolved measurements of the radiation on the moon.
New biomaterial could shield against harmful radiation
Northwestern University researchers have synthesized a new form of melanin enriched with selenium.
A new way to monitor cancer radiation therapy doses
More than half of all cancer patients undergo radiation therapy and the dose is critical.
Nimotuzumab-cisplatin-radiation versus cisplatin-radiation in HPV negative oropharyngeal cancer
Oncotarget Volume 11, Issue 4: In this study, locally advanced head and neck cancer patients undergoing definitive chemoradiation were randomly allocated to weekly cisplatin - radiation {CRT arm} or nimotuzumab -weekly cisplatin -radiation {NCRT arm}.
Breaking up amino acids with radiation
A new experimental and theoretical study published in EPJ D has shown how the ions formed when electrons collide with one amino acid, glutamine, differ according to the energy of the colliding electrons.
Radiation breaks connections in the brain
One of the potentially life-altering side effects that patients experience after cranial radiotherapy for brain cancer is cognitive impairment.
Fragmenting ions and radiation sensitizers
The anti-cancer drug 5-fluorouracil (5FU) acts as a radiosensitizer: it is rapidly taken up into the DNA of cancer cells, making the cells more sensitive to radiotherapy.
'Seeing the light' behind radiation therapy
Delivering just the right dose of radiation for cancer patients is a delicate balance in their treatment regime.
Radiation contamination at a crematorium
Radioactive compounds known as radiopharmaceuticals are used in nuclear medicine procedures to diagnose and treat disease.
More Radiation News and Radiation Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.