Face Paint That Can Read Your Heartbeat

The colorful tiger painted on a patient’s arm may look like face paint.

But it can also work as a medical sensor.

Engineers at Penn State University have developed a conductive ink that can be painted directly onto the skin to monitor signals from the heart, muscles, and brain.

The material can also be tinted with ordinary food coloring, allowing it to be turned into designs ranging from cartoon animals to superheroes.

Co-author Larry Cheng compared the material to face paint.

The ink goes on nearly transparent and dries in less than 10 minutes, or faster with a hair dryer.

Unlike traditional stick-on electrodes, the painted sensor sits directly against the skin without leaving an air gap.

That can matter because gaps between an electrode and the skin can interfere with signal quality, especially when a person is sweating or has body hair, according to doctoral student Wanqing Zhang.

The researchers reported their findings in the Proceedings of the National Academy of Sciences.

In one test, a painted electrode tracked a person’s heart activity for 12 hours during normal daily activities and continued to provide useful readings during exercise.

In another experiment, electrical signals from a person’s forearm were used to control a robotic hand without physical contact.

The technology is still being developed.

The research team has filed a provisional patent and hopes future versions could be adapted to detect biomarkers such as glucose or cortisol.

One possible use may be in pediatric care.

A sensor painted as a superhero, animal, or other familiar design could be less intimidating for a child than traditional medical electrodes and wires.

The appeal is easy to see.

What looks like a temporary piece of body art could someday also serve as a medical sensor.