Wristband Device Tracks UV Exposure

A new study describes how a low-cost ultraviolet (UV) dosimetry wristband can warn users when their exposure to the sun has become dangerous.

Developed by researchers at the University of Granada (UGR; Spain), and RMIT University (Melbourne, Australia), the paper-based wristband can provide spectrally selective colorimetric monitoring of ultraviolet radiations (UVR) with the aid of a photo-electrochromic ink that consists of a multi-redox polyoxometalate, an e− donor, and transparency sheets. Importantly, the real-time solar dosimeters also meet the specific need of different skin colors, which demands personalized sensors.


The researchers have created six versions of the color-changing wristbands, each personalized for a specific skin tone, as darker people need more sun exposure to produce vitamin D, essential for healthy bones, teeth, and muscles. The paper-based sensor features happy and sad emoticon faces, drawn in an invisible UV-sensitive ink that successively lights up at 25%, 50%, 75%, and 100% of daily recommended UV exposure. The study was published on September 25, 2018, in Nature Communications.

“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. 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,” said senior author Professor Vipul Bansal, PhD, or RMIT. “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. The low cost and child-friendly design of these UV sensors will facilitate their use as educational materials to increase awareness around sun safety.”

Currently, the only guide for managing sun exposure is UV index, which only indicates the intensity of UV rays, and cannot monitor individual phototypes daily exposure. For example, 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 also has application beyond the health sector, as over time UV rays can have damaging effects on the lifetime of many industrial and consumer products.

Related Links:
University of Granada
RMIT University