An international team of researchers led by RMIT University has developed paper-based UV sensors that could help people manage vitamin absorption and avoid sun damage.
UV active ink can be printed on paper making sensors cheap and easy to produce. Image credit: RMIT University.
While humans do need some sun exposure to maintain healthy levels of vitamin D, excessive exposure can cause sunburn, skin cancer, blindness, skin wrinkling and premature signs of aging.
Diseases such as lupus and many medications increase the photosensitivity of our skin and reduce our ability to absorb vitamins through diet, making monitoring our sun exposure thresholds highly individual.
Professor Vipul Bansal, a researcher in the RMIT University’s School of Science, and his colleagues from Australia and Spain combined a photoelectrochromic ink with simple components such as filter paper and transparency sheets to fabricate low-cost UV sensors.
“We are excited that our UV sensor technology allows the production of personalized sensors that can be matched to the specific needs of a particular individual,” Professor Bansal said.
“The low cost and child-friendly design of these UV sensors will facilitate their use as educational materials to increase awareness around sun safety.”
Knowing what a healthy amount is for you depends on understanding your personal classification, from type I to VI, as each has very different solar exposure needs.
Fair skin (type I) can only tolerate only one fifth of the UV exposure that dark skin (type VI) can before damage occurs, while darker types require longer in the Sun to absorb healthy amounts of vitamin D.
“The discovery could help to provide people with an accurate and simple measure of their personal exposure levels throughout the day,” Professor Bansal said.
“We can print our ink on any paper-like surface to produce cheap wearable sensors in the form of wrist-bands, head bands or stickers for example.”
Currently the only guide for managing sun exposure is UV index however this blunt tool only indicates the intensity of UV rays.
It does not act as a precise tool to monitor each individual’s daily exposure.
“The discovery has application beyond the health sector as over time UV rays can have damaging effects on the lifetime of many industrial and consumer products,” Professor Bansal noted.
“Monitoring this exposure could help improve the safety and reliability of a range of items, including vehicles and military equipment, with huge potential cost savings.”
The team’s work appears in the journal Nature Communications.
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Wenyue Zou et al. 2018. Skin color-specific and spectrally-selective naked-eye dosimetry of UVA, B and C radiations. Nature Communications 9, article number: 3743; doi: 10.1038/s41467-018-06273-3
