Highly porous synthetic melanin can protect skin from toxins, radiation

When applied to fabric, synthetic melanin successfully blocked harmful materials while letting good stuff, like oxygen and water, pass through. Photo by Northwestern University
When applied to fabric, synthetic melanin successfully blocked harmful materials while letting good stuff, like oxygen and water, pass through. Photo by Northwestern University

March 5 (UPI) -- Scientists have successfully synthesized melanin, a selectively porous material capable of trapping a variety of toxins, including radioactive particles.

Initially, researchers set out to replicate the melanin produced by certain exotic fungi, species known to colonize harsh environs, such as spaceships, dishwashers and nuclear fallout zones like Chernobyl.


Their efforts -- described Monday in the Journal of the American Chemical Society -- produced a highly porous material with potential for a variety of applications.

"You're always excited by discovering something that's potentially useful," study co-author Nathan Gianneschi, professor of chemistry at Northwestern University, said in a news release.

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"But there's also the intriguing idea that by discovering this, maybe more materials like this exist out there in biology already. There aren't many examples where chemical synthesis leads to a biological discovery. It's most often the other way around," Gianneschi said.

Fungi aren't the only organisms that use melanin. The material is found on our skin and the back of our eyes. In fact, melanin is produced by a diversity of plants and animals.

On our skin, melanin helps protect our tissue from harmful solar radiation. The material plays similar protections for other species. For example, when turtle-headed sea snakes inhabit polluted waters, their stripes darken as melanin traps toxins.

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Inspired by nature, Gianneschi and his research partners wanted to find out if they could enhance the melanin's absorption qualities -- and in the process, gain insights into how exactly melanin works.

"Melanin's function isn't fully known all the time and in all cases," Gianneschi said. "It's certainly a radical scavenger in human skin and protects against UV damage. Now, through synthesis we've happened upon this exciting material that very well may exist in nature. Fungi might make this material to add mechanical strength to their cells, but it is porous, allowing nutrients across."

In lab tests, researchers used electron microscopy to observe the performance of synthesized melanin. The material's pores were able to trap and hold harmful particles while letting air, water and nutrients pass through.

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In followup tests, scientists isolated fungal cells containing melanin by etching away biomaterial until only a shell like structure -- filled with melanin -- remained. Scientists dubbed the structures "fungal ghosts."

Similar to their synthesized melanin, the fungal ghosts trapped toxins but allowed water to filter through.

Researchers suggest the biomaterial could be replicated and used as a protective layer on fabrics or applied to masks and face shields.

Additionally, if exotic fungi species have been using especially protective melanin for millions of years, they may hold other biomaterial secrets.


"Fungi can thrive in places where other organisms struggle, and they have melanin to help them do it," said first author Naneki McCallum, a graduate student researcher in Gianneschi's lab. "So, we ask, what are the properties that we can harness by recreating such materials in the lab?"

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