Using tattoos in medicine

Tattoos nowadays are used as decorative body ornamentation, but what if they can have another function? Scientists have developed a thin film that can be implanted right under the skin, like a tattoo, to show the amount of oxygen in the blood. 

The thin film consists of a protein derived from silk that is biodegradable and biocompatible. So, unlike tattoos, the film will be degraded and excreted by the body after a few weeks to a few years. This degradation time can be altered depending on the time you want the tattoo to be present in the body. Added to the film is a complex molecule that glows in the presence of near-infrared light.

The duration of the glow after removing the near-infrared light source is determined by the concentration of oxygen present in the surrounding tissue. The higher the concentration of oxygen, the shorter the glow lasts. So, if you shine a light on the tattoo and the glow fades immediately after removing the source, you have a lot of oxygen in your blood. While, if the glow lasts for a long time, this is a signal that your oxygen level is low.

Although we already have a method to measure the oxygen concentration in the blood without actually extracting blood, this oxygen sensing tattoo is a promise for innovation in blood monitoring. It could be the first step toward sensors for glucose, lactate, or electrolytes without requiring blood samples.