Applications in the areas of medicine, recreation and food waste prevention
OLED technology has been incorporated in consumer items, such as smartphones and televisions, and could end up in something less conventional: tattoos. Their use reaches beyond the glowing body painting, with possible uses in the fields of medicine, athletics and even food waste reduction.
This OLED smart tattoos are not, as in the standard version, applied into the dermis layer of the skin using a needle. Instead, they are applied in the same manner as temporary tattoos—by tapping them with water until they are cleaned using soap.
The squad at the University College London (UCL) and the Italian Institute of Technology are behind the tattoos. They use a 76-nanometer-thick light-emitting polymer using a method called spin coating, in which the polymer is added to a substrate that is spun at high speed, which creates an incredibly thin and even film.
The electroluminescent polymer, which emits light when exposed to an electrical field, is placed between a pair of insulating layer-protected electrodes and transferred to commercial tattoo paper. The tattoo added is just 2.3 micrometres deep, approximately a third of the thickness of a single red blood cell.
“The tattooable OLEDs that we have demonstrated for the first time can be made at scale and very cheaply,” says UCL’s Professor Franco Cacialli, in a statement. “They can be combined with other forms of tattoo electronics for a very wide range of possible uses. These could be for fashion – for instance, providing glowing tattoos and light-emitting fingernails.”
The tattoos have other applications than look cool. “In athletics, it may be paired with a sweat sensor to signal dehydration. In health care, they could release light when a patient’s condition changes—or, if the tattoo was transformed in the other direction into the flesh, they could theoretically be paired with light-sensitive cancer target therapies, for example.”
The team played with applying tattoos to glass, rubber, and even fruit. This may cause them to be added to food packaging, signalling that the contents have past their expiry date.
In their current shape, tattoo sensors easily degrade once they are exposed to air, but researchers are working on this issue, along with how to incorporate a tiny power supply.