The UV active ink can be printed on paper making sensors cheap and easy to produce. Source: RMIT University The UV active ink can be printed on paper making sensors cheap and easy to produce. Source: RMIT University

A sticker capable of monitoring a wearer’s ultraviolet exposure is one step closer to reality thanks to wearable sensors that make it easier for people to avoid sun damage.

In research led by Professor Vipul Bansal of the Royal Melbourne Institute of Technology (RMIT), color-changing sensors have been developed in six different types to reflect the range of human skin tones. The team believes that such a development might offer those wearing the sticker a simple and more accurate measure of the wearer’s sun exposure over the course of the day.

"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," Bansal said.

Although too much exposure to the sun can result in sunburn, blindness, wrinkling, premature skin aging and skin cancer, some sun exposure is necessary for achieving healthy Vitamin D levels.

According to the research, determining what those healthy levels are means understanding a person’s individual skin type classification, which can range from Type I to Type VI, with each representing different solar exposure needs.

For instance, Type I fair skin can only handle a fifth of the UV exposure that a person with Type VI dark skin can.

"We are excited that our UV sensor technology allows the production of personalised sensors that can be matched to the specific needs of a particular individual," said Bansal.

"The low cost and child-friendly design of these UV sensors will facilitate their use as educational materials to increase awareness around sun safety."

The only guide for managing sun exposure currently in use is the UV index, which only serves to indicate the intensity of UV rays and is not a tool designed to monitor personal daily exposure.

The paper titled, "Skin color-specific and spectrally-selective naked-eye dosimetry of UVA, B and C radiations" has been published in Nature Communications.

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