Temporary ‘tattoo’ measures glucose levels

In the earliest stages of development, this wearable monitor extracts and measures the amount of glucose between skin cells.

The researchers, led by graduate student Amay Bandodkar in Professor Joseph Wang’s laboratory at the NanoEngineering Department and the Center for Wearable Sensors at the Jacobs School of Engineering, admit that their prototype does not provide a numerical readout and only lasts for a day. But they are working on making the tattoo last longer and to incorporate Bluetooth capabilities so that glucose readings can be sent directly to a healthcare provider or stored in the cloud.

This flexible tattoo monitor is made of a series of electrodes printed on temporary tattoo paper. By delivering a mild electric current to the skin, the device forces sodium ions in the fluid between skin cells to move toward the electrodes. A built-in sensor then measures the strength of the electrical charge produced by the glucose to determine the glucose level.

"The concentration of glucose extracted by the non-invasive tattoo device is almost hundred times lower than the corresponding level in the human blood," said Bandodkar in a press release. "Thus we had to develop a highly sensitive glucose sensor that could detect such low levels of glucose with high selectivity."