Will it stick? Biodegradable nanoparticles developed by Yale scientists to revolutionize sunscreen

The sunblock agent developed by Yale researchers would bind to skin via covalent bonding. This adhesion would decrease the negative impacts of sunblock in regards to cell damage and skin irritation. Image courtesy of Flickr

Have you ever forgotten to apply sunscreen at the beach? The sting of red skin after a day in the sun is a not so subtle reminder of the damages of UV radiation. Traditional sunscreens may seem like the answer; however, some of the molecules which provide UV protection can be absorbed into the bloodstream or make the skin vulnerable to cellular damage. These molecules can also cause allergic dermatitis, a condition that results in an itchy rash when the skin comes in contact with particular substances. To address these issues, Yale researchers are pioneering the development of safer sunscreen. 

The UV spectrum is split into different wavelength categories: UVB is shorter wavelength radiation that causes redness while UVA is longer wavelength and penetrates deeper into the skin. To gain full spectrum protection it is essential that sunscreen contains a mix of molecules such as avobenzone, which blocks UVA, octocrylene, which blocks UVB, and photostabilizers, which prevent the breakdown of these molecules in the presence of light.

In a recent paper published in the Journal of Bioengineering & Translational Medicine, scientists from the Saltzman research group presented how sunscreen ingredients such as avobenzone and octocrylene can be encapsulated in Bioadhesive Biodegradable Nanoparticles (BNPs) to protect the skin from coming into direct contact with UV blocking molecules. BNPs containing UV blocking molecules stick above the skin, delivering the molecules to their functional location while preventing adverse effects from absorption or direct skin-molecule contact. BNP’s provide the added benefit of removing the need for any additional photostabilizers. “You are getting two uses out of one molecule,” lab leader Mark Saltzman describes referencing octocrylene. When the two molecules are encapsulated together within the BNPs, octocrylene acts to photostabilize avobenzone.

These findings mark notable progress by the Saltzman group’s initial foray into BNP sunscreens. “In our initial study, we used the simplest possible UV blocking ingredient, a molecule called padimate,” explains Saltzman, referencing his 2015 collaboration with Yale School of Medicine dermatologist Michael Girardi. “We used that ingredient because it was cheap and it worked.” The switch to more common ingredients such as octocrylene and avobenzone has proved successful, after recent in vitro water resistance tests and a clinical study run by Giradi showed promising results. Underwater, the particle retention to skin is eighty-five percent over three hours while protection against UV radiation was found to be comparable to the FDA standard P2.

So, will this sunscreen be hitting the shelves anytime soon? “It’s not like any other sunscreen currently out there so there are some challenges to getting it to work,” notes Saltzman. But good news is on the horizon: last year a French start-up company called Nanosive licensed Yale’s patents on the technology with the aim of developing it into a commercial product. Saltzman provides insight to their plans: “Their goal is to get it on the shelves between eighteen months and two years. I’m optimistic; I hope that they’re successful.”  

In the meantime, Saltzman and his group plan to continue their work on BNPs by investigating how they can be used for the prevention of sunlight induced diseases like melanoma. The group also hopes to explore the particles’ abilities in treating other skin diseases.