Today’s Solutions: June 26, 2022

Spring is just around the corner—but before we get too excited to throw on our swimsuits and sunbathe in the park, it’s important to remember that we have to be careful when it comes to sun exposure. 

Even though those lovely warm rays may feel great against bare shoulders, it’s been well established that spending too much time in the sunshine can be dangerous. That’s why scientists at Northeastern University have come up with a convenient technology that alerts the user if they’ve had enough sun exposure and should move to a shady spot.

The development of this technology came from a completely different project. The scientists were originally trying to study how tentacled sea creatures like squid are able to camouflage effortlessly within their environments.

The team had been working on identifying a range of pigments, chemical reactions, and mechanisms that help the creatures blend in and discovered that one molecule called xanthommatin, is central to the process.

Once they pinpointed the molecule that gives squid its visible color, the team explored how it could potentially be worked into clothing or other consumer products. However, they were frustrated to find out that when xanthommatin was left in ambient light, it would end up changing color. 

“When we noticed it changed color in light, we were super annoyed,” reveals Leila Deravi, assistant professor of chemistry and chemical biology at Northeastern University. However, some of Deravi’s team thought that this annoyance could be an opportunity to pivot toward designing a new form of UV sensor. 

They went on to design a finger-tip-sized device that could be worn on a shirt or bathing suit. There is also a “button” on the device that releases fluid from a small reservoir on its edge that travels through channels cut into the plastic and hydrates the round piece of paper treated with the xanthommatin pigment that is worked into the device. This activates the device, which results in wet paper that will then react to UV radiation, changing from a yellow-orange color to a bright red as it becomes exposed to more UV.

“We all know more or less that too much sun on a high-UV-index day is bad. But we don’t necessarily know how that translates to time in the sun,” explains study author Dan Wilson. “This is meant to provide a visual, qualitative indication of when you may have been in the sun for too long and you should consider spending some time in the shade or reapplying your sunscreen.”

Tests indicate that the little sticker device could be used in a range of conditions, and could even be coated in sunscreen, which caused it to change color more slowly.

The team believes that their device won’t only be useful for monitoring sun exposure but could be utilized in other situations in which UV radiation must be measured, like when sterilizing surfaces.

Source study: ACS Sensors—Wearable light sensors based on unique features of a natural biochrome 

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