A sensor that sticks to the skin can give colour-coded readouts of ultraviolet light levels from the Sun, the leading cause of skin cancer.
John Rogers at the University of Illinois at Urbana–Champaign and his colleagues developed the stretchable device (pictured), which is less than one-fifth of a millimetre thick. It has several layers, including a compound that changes the colour of a dye when activated by UV light; filters to monitor both UV-A and UV-B radiation levels; and a small chip that wirelessly sends signals to a nearby device.
The technology could be used to manage UV exposure on certain regions of the body, and could be adapted to sense other types of environmental exposure, such as pollution and chemical or biological agents, the authors say.
Adv. Funct. Mater. http://doi.org/f3s7dr (2016)