A custom bio-ink developed by Clarkson University researchers could enable wearable sensors designed to increase the wearer’s awareness of UV exposure.
Noting the prevalence of skin cancer and the fact that most exposure to UV radiation is intermittent and at varying levels, professor Silvana Andreescu of Clarkson’s Department of Chemistry and Biomolecular Science and her team set out to develop a technology capable of detecting and quantifying UV radiation exposure as it happens in a portable, low-cost device.
“We decided to explore the capabilities of 3D bioprinting to manufacture these wearable UV-responsive sensors, as 3D printers have become inexpensive and accessible,” Andreescu said.
The sensor relies on photocatalytic titanium dioxide nanoparticles that degrade colored dyes encapsulated within a 3D printed hydrogel when exposed to UV radiation. The sensing time varies, Andreescu told Photonics Media.
“For strong UV radiation, the color change is almost instantaneous and progresses over time depending on the intensity of radiation,” she said. “The sensor can monitor continuous exposure over several hours.”
The device was first tested with a solar simulator that mimics natural sunlight in a laboratory setting. Optimized sensors were then tested outdoors in natural light and their responses were related to the UV index on the day of exposure, Andreescu said.
The researchers envision the device being commercialized either as a 3D-printed wearable or as a changeable sensor inserted within a thin thermoplastic polyurethane layer. An app could be used to scan the colorimetric response to compare with a calibrated chart to measure the level of UV radiation, Andreescu said. The sensor could also have applications in UV sanitation where it could indicate whether items have had adequate exposure to UV light for sanitation.
The research was published in ACS Applied Materials and Interfaces (www.doi.org/10.1021/acsami.0c12086).