Ultrathin biosensors

Scientists have made conductive "transfer tattoos" from graphene

Grigory Kopiev, N+1

Scientists from the University of Texas at Austin have learned how to create graphene sensors applied to the skin. In them, a layer of graphene is bonded with a water-washed material. Thus, the sensor can be applied to the skin in the same way as "transfer tattoos" are applied: by gluing and rinsing with water. The study is published in the journal ACS Nano.

By measuring the parameters of the skin, you can learn a lot about the processes taking place in the body. For example, it can be used to judge the activity of the heart or brain – for this, metal electrodes are usually attached to a person. But they can strongly squeeze the skin and make the patient feel uncomfortable, or they do not fit well to the skin and reduce the contact surface. Recently, scientists have been experimenting with sticker sensors that are applied directly to the skin; as a rule, they use metal for this - for example, gold.

American researchers decided to use another conductive material, graphene, for the same purpose. Since it is impossible to simply apply a graphene monolayer to the skin or grow it directly on it, scientists used a more complex scheme. First, graphene is grown on a copper substrate, then a polymer is applied to graphene, and the copper is removed. In order for the "tattoo" to be easily applied to the skin, a special transfer paper was applied to it. After a person presses the sticker with the graphene side to the skin, it can be fixed with water, similar to how transfer tattoos are applied.

Scanning electron microscope studies have shown that more than half of graphene is represented as a monolayer with a thickness of one carbon atom. The total thickness of the "tattoo" is less than half a micrometer, and the transparency is about 85 percent. Due to this, as well as the fact that its elasticity is higher than that of the skin, such a sticker is almost invisible to a person. The researchers also showed practical applications of such material for removing physiological indicators, for example, pulse or temperature.

Many scientists are engaged in the creation of skin electronics. For example, polymer transistors-pull-ups, which almost do not lose their properties when stretched. Other researchers are creating electronics directly on the body, printing it using a special 3D printer on the skin.

Portal "Eternal youth" http://vechnayamolodost.ru  28.08.2017