Medical devices such as pacemakers, insulin pumps or heart monitors provide vital monitoring, but they can get in the way. The newest healthcare wearables, on the other hand, are so thin and flexible that patients might even forget that they’re wearing them at all.

What Is an E Tattoo?

Electronic tattoos (also called e tattoos or digital tattoos) are similar to temporary tattoos for children — you get them damp, hold them to your skin, and then they stick for a few days or until you rub them off. While children’s tattoos are simply decorative, medical tattoos can monitor important biomarkers such as heart rate, blood pressure, hydration or blood sugar levels.

An e tattoo can be made of flexible electronic components such as conductive ink that can track important information about the person wearing it. According to Carnegie Mellon University, these tattoos are made using a liquid metal alloy to print ultrathin circuits. Just like a child’s decorative tattoo, you need to get it damp to apply to the skin. Unlike traditional medical devices, these tattoos have properties that are similar to lightweight fabrics — they conform to any shape and still work even if you bend, fold, twist or strain them. It’s like having a smart Band-Aid, or the human body equivalent of IoT.

Digital tattoos are only possible because of new developments in 3D printing and circuit printing technologies. The Medical Futurist explained that digital tattoos can be made of materials such as gold nanorods, graphene or various polymers with a rubber backing. When the tattoo is attached to the skin, tiny electrodes can record information about the wearer and transmit it to smartphones or other connected devices. They could eventually replace other wearable technology because they’ll be more accurate due to direct and constant contact with the skin. Plus, they can operate without batteries because they can receive energy through electrophysiological processes. For example, Technology Networks described healthcare wearables that are powered by the piezoelectric effect, which means they can generate an electric charge in response to applied mechanical stress.

Applications for Healthcare Wearables

Just like traditional medical devices, healthcare wearables can track biomarkers that help patients and doctors monitor critical health conditions. These small, non-invasive devices could allow healthcare experts to monitor and diagnose heart rhythm problems (arrhythmia), heart activities of premature babies, sleep disorders and brain activities, according to Medical Futurist. They’re as easy to wear as an adhesive bandage, but instead of covering a wound, they continuously monitor patients. They could even send alerts to medical systems. For example, if a patient’s heart rate becomes critical, the device could automatically call an ambulance and transmit data to emergency medical staff.

Here are three examples of this innovative healthcare technology, as detailed by Medical Futurist.

1. Massachusetts-based company MC10 created a digital tattoo that can monitor movement, muscle performance or heart activity. The device uses stretchable metallic interconnects and rubbery polymers that form a system that can “sense, measure, analyze, and communicate information” about the person who wears it. It is thinner than a strand of human hair.
2. Researchers from Harvard and MIT developed color-changing tattoos called Dermal Abyss, which can track dehydration and glucose levels for people with diabetes. The tattoos use special inks that can measure the concentration of glucose, sodium and pH in the skin. For example, the ink’s color “intensifies as the wearer’s sodium levels rise, which is often a sign of dehydration,” or changes from green to brown when glucose levels rise, which could be used by diabetics to monitor their blood sugar levels.
3. South Korean researchers created a similar glucose-monitoring patch that goes a step further to also administer medication. A team at Seoul National University developed sensors that can detect body temperature and the pH/chemical composition of the sweat of people with Type 2 diabetes. The device transmits the data to a smartphone app that determines the correct amount of medication based on the status of the wearer’s sweat. Then a tiny needle array in the patch injects medicine right into the person’s body.

Outlook for Wearable Medical Devices

As healthcare technology gets smaller and smarter, wearables such as e tattoos could minimize the ways in which essential medical devices interfere with a patient’s life. Most e tattoos are still in the research and development stage. Eventually, these devices could be less invasive than traditional methods, while also being just as accurate and reliable as current devices. Plus, they do look pretty cool, which might mean that more people would want to wear these life-saving devices.