Tattoo for diabetics

To control blood sugar levels, diabetics have to apply a drop of blood from a finger to a test strip once or several times a day - the procedure is unpleasant, expensive and, most importantly, one–time. Implantable microsensors in the form of thin tubes about a centimeter long made it possible to speed up and facilitate glucose control and make it possible to do this with any frequency, but all of them are still in development. Heather Clark and her colleagues from the research Laboratory named after Draper (Draper Laboratory, Cambridge, Massachusetts) is developing an even more ingenious method for determining the concentration of sugar in the blood – using nanosensors that can be injected into the surface layer of the skin, like tattoo ink.

A tattoo in which microscopic (120 nm in size) beads of a biocompatible polymer filled with a fluorescent dye and a glucose–sensitive substance are used as a dye, when the sugar level rises, it will glow in the infrared range - the stronger the more of the analyzed substance is in the intercellular fluid.

In animal experiments, a tattoo sensitive to sodium concentration regularly glowed when a saline solution was injected into rodents (the picture shows a separate "tattooed" cell glowing in a tissue with a high sodium content). Similar glucose-sensitive sensors have already been developed, but have so far been tested only in vitro.

The researchers suggest that their nanosensors will be injected into the surface layer of the skin, not as deep as permanent tattoo ink, and from time to time, as the surface layers of the skin peel off, the procedure will have to be repeated. Readings can be read using a photosensitive element mounted in a monitor similar to a computer mouse. Sensors can be configured not only for sodium and glucose, but also for other substances, but this is a matter of the future.

Although polymer nanosensors did not cause an immune reaction in animals, this should be carefully rechecked, since the number of immune cells increases at the site of inflammation, including macrophages that consume glucose and reduce its local concentration. In addition, the intensity of the signal can be influenced by various factors, including age and skin color.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of Technology Review

28.01.2009