At the local office supply store, a rollerball gel pen will set you back about 50 cents. With a little tinkering, researchers take that same pen and use it to measure glucose levels.
Nano-engineers at the University of California, San Diego have invented a technique that turns cheap pens into do-it-yourself sensor dispensers. They replace regular gel with custom biochemical ink that can measure specific chemicals.
When drawn on the body, the ink sticks much like a temporary tattoo. It can detect things like sodium, lactate, and glucose insulator amounts in your sweat. To read the measurements, the group is creating a Bluetooth-enabled electrical device that will take the information from the sensor used and transfer it to a smartphone or laptop.
For diabetics who need to check their blood sugar daily, this could be a cheaper alternative to pre-made glucose strips. (Earlier this year, another group of researchers tested a temporary paper tattoo that measured glucose levels using a small electric shock.)
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Currently, the designs can only provide a single measurement, but researchers would eventually like to run a single tattoo for all-day monitoring. The pen encourages creative doodling, which could be attractive to children.
“The goal was to have a system that can be used easily by any untrained end user to develop sensors on their own,” said Amay Bandodkar, a fourth-year graduate student at UC San Diego who created the pen. The work was led by Professor Joseph Wang in the Department of Nanoengineering.
The applications are not limited to the human body. To measure toxins in the air, such as phenol, the group tapped into the leaves of plants. The ink is non-toxic and will not damage foliage.
Although still in the early stages of developing the technology, the researchers plan to expand the number of chemicals the pen can detect.
Bandokar believes the technology, called enzyme sensors, could serve a wide range of real-world uses. For example, a soldier might draw a line on a wall to detect explosives or gunshot residue. In some situations, the drawing could blend into its surroundings without arousing suspicion.
CNN Money (San Francisco) First published March 10, 2015: 8:41 a.m. ET