科学美国人60秒:Fish Slime Inspires New Eco-Sunscreen Ingredient

Anyone who’s gone snorkeling at a coral reef lately may have been discouraged from slathering on too much sunscreen. In some places, the non-biodegradable skin protection is actually banned. That's because researchers reckon that some four to six thousand tons of sunscreen float off the skin of snorkelers every year, enveloping corals in a cloud of chemicals—chemicals that can sicken or even bleach the coral.

But a more eco-friendly way of saving our skin might be to copy nature's tricks. Algae and cyanobacteria produce sunlight-absorbing compounds. So do reef-dwelling fish, in the protective slime on their bodies. Researchers isolated those molecules, called mycosporines, which absorb both UV-A and UV-B rays. 

Mycosporines have actually been used before in a few SPF products, but in a form that can both penetrate our skin, and easily wash off.

So the biochemists attached the mycosporines to chitosan, a polymer derived from the shells of shrimp and crabs. This hybrid package, they say, is a more effective sunscreen, with constituents too big to pass into the skin, and it’s more resistant to washing off. It's also hypoallergenic, and did not affect cell development, in in-vitro tests. The findings appear in the journal Applied Materials & Interfaces. [Susana C.M. Fernandes et al, Exploiting Mycosporines as Natural Molecular Sunscreens for the Fabrication of UV-Absorbing Green Materials]

The researchers say that besides providing a superior sunscreen, this material could also lead to more durable paints and plastics—think lawn chairs, and other outdoor items that take a beating from light and heat. And to be clear—this stuff is not being bottled just yet. But it could be soon, they say. Which could help protect the environment, in addition to saving our skin.

—Christopher Intagliata

[The above text is a transcript of this podcast.