Damage caused by ultraviolet (UV) radiation in sunlight is the leading preventable cause of skin cancer in the U.S.; hence, dermatologists often advise people to apply sun protection daily to reduce their risk.
There are chemical sunscreens that absorb into the skin and do not leave a cast. Still, many people prefer mineral sunscreens, which leave a white cast on their skin. This annoying white, chalky cast on the skin discourages people, especially those with darker skin tones, from using sunscreen altogether.
Such was the case of AJ Addae, an innovative scientist and cosmetic entrepreneur who studies chemical biology at UCLA. “They leave this white cast on my skin, and it deters me from wanting to use sunscreens,” Addae said to KABC.
Addae knew there had to be a solution, so she spoke with her professor, Dr. Paul S. Weiss, who is with the UCLA Jonsson Comprehensive Cancer Center, to find a way to address the problem.
Weiss said, “We took apart conventional sunscreens that use zinc oxide and learned that the white cast comes from agglomeration of these round, somewhat irregular particles of zinc oxide.”
Having realized that the round particles cause the clumping, they decided to make zinc oxide in a different shape.
A statement by UCLA said most zinc oxide used in sunscreens is produced through chemical processes that create very small, roughly round nanoparticles. In the new study, Addae and her team “tested zinc oxide made using a patented high-temperature flame process that produces much larger particles shaped like tiny tetrapods,” the statement added.
“Because of their structure, these tetrapod-shaped particles have standoffs and form porous networks instead of collapsing into clumps,” said Addae in the statement. “They can’t pack tightly and aggregate, so they stay evenly distributed in the sunscreen.”
Addae and her team worked with a University of Denmark researcher who had previously worked with tetrapods.
The new tetrapod shape did not affect the protective performance of the sunscreen, as stated in the researcher’s American Chemical Society paper.
“We were happy to see that it did absorb really similarly to other zinc oxide types that are on the market,” Addae said to KABC.
The other good news is that tetrapod zinc oxide needs no solvent, making it a greener option, Addae, a doctoral candidate in chemical biology at UCLA, noted.
“When I spread it on my own skin, I didn’t get that white cast I usually see with zinc oxide,” said Addae to UCLA. “That was the moment I realized this could really work.”
“What surprised us was how quickly it worked,” added Weiss, who is also a member of the California NanoSystems Institute at UCLA and the UCLA Goodman-Luskin Microbiome Center. “The very first formulations already showed a visible difference.”
“I think it’s going to be a good step in the right direction for getting everyone to wear sunscreen and prevent skin cancer,” Addae indicated.
Currently, further testing is still needed before the technology reaches the market, the researchers said.
