Humans aren’t the only organisms that need sunscreen to avoid DNA damage inflicted by ultraviolet light. Many tiny inhabitants of shallow waters such as cyanobacteria and algae also need sun protection, but they make their own. A team led by Diego Sampedro at the University of La Rioja were inspired to design new sun protection for humans based on these microbe-produced sunscreens.
The scientists focused on a family of small molecules called mycosporine-like amino acids (MAA), which contain a central cyclohexenone or cyclohexenimine ring that is further decorated by a variety of chemical substitutions (Angew. Chem. Int. Ed. 2017, DOI: 10.1002/anie.201611627).
These molecules have a lot of characteristics desired by sunscreen makers: They’re low weight, they’re thermally and photochemically stable, and they dissipate the energy from absorbed UV light as heat. The molecules’ downside is their elaborate chemical decoration: Building many of these MAAs in a lab takes more than a dozen steps—too many to make their production financially feasible for sunscreen makers.
So Sampedro’s team used computer modeling of MAAs to predict the simplest core structure that might still produce desirable UV protection. Using this as a starting scaffold, the team built a collection of analogs that were more amenable to large-scale production. When the team added its new compounds to commercial products, the sunscreens boosted protection against both UV-A and UV-B wavelengths.
The team hopes the molecules could provide UV protection in nonsunscreen applications as additives to polymers, resins, paints, or coatings.