To keep diabetes under control, patients sometimes have to check their blood sugar as many as eight times a day–before and after every meal or snack, before and after exercise, before bed, and in the middle of the night. It’s a little like a part-time job, and it hurts: Each test requires a painful finger prick with a needle, so patients sometimes avoid it. But that may soon change.
When you stick a new paper-based temporary tattoo on your arm, it can estimate glucose levels in your skin. Eventually, the tattoo will be able to send that data directly to a doctor, or store it in the cloud. The sensor is in development now in Joseph Wang’s nanoengineering lab at UC San Diego’s Center for Wearable Sensors.
“The non-invasive nature of our tattoo sensor, as well as its low cost, are some of the major advantages as compared to other technologies,” says graduate student Amay Bandodkar, who is working on the device.
Each tattoo costs only a few cents, a fraction of the cost of current $2 test strips, and the researchers are working to bring that down even more. The sensor is also reliable. Even though it can’t give results in real-time, like a needle, it can give a clear estimate. It uses electrodes to mildly zap skin; if glucose levels are high, they’ll produce a strong electrical charge in response.
It’s as simple to use as a typical temporary tattoo–all someone has to do is apply it with a little water and then peel the paper away.
The tattoos could also eventually be used for non-diabetics. In other experiments, the research team has shown that the tattoos can measure things like physical stress or electrolyte imbalance. They can even generate renewable power; tattoo biofuel cells can make electricity from sweat, and that could eventually be used to power wearable electronics.
For now, the researchers are focused on improving the sensor design for diabetics, helping it last longer (the current iteration lasts about a day), and creating a wearable device that can display the results.
“At present, we have demonstrated a proof-of-principle and much optimization needs to be done,” Bandodkar says. “It will take at least a few years of dedicated research before it can be made commercially available.”
When it comes to market, it might join other devices like Google’s concept for a smart contact lens that can measure glucose in tears. Eventually, needles might be a thing of the past. The tattoos could also make it easier to collect data from millions of people at a time, so researchers may be able to better understand the disease.