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Electronic Tattoos and the Next Generation of 3D Printing Applications

Electronic tattoos
Image credit: College of Engineering, Carnegie Mellon University


3D printing has already brought tremendous benefit to a diverse range of industries. In product development, engineers have been able to turn to 3D printed models to quickly build their own prototypes, enabling rapid iteration and innovation. Photovoltaic printed electronics have proven to be a flexible and lightweight alternative to traditional solar cells. And additive manufacturing has enabled the aerospace industry to generate lightweight components for their aircrafts at costs far lower than traditional manufacturing. Total 3D printing sales among public companies are expected to top $3 billion in 2020, according to Deloitte.

In the healthcare space, we’re just starting to realize the possibilities of wearable 3D printed electronics, or e-tattoos. Here’s a look at what this promising field has in store.

What are electronic tattoos?

Electronic tattoos are lightweight, flexible circuits made from a liquid metal alloy that can conduct electricity, which are printed onto temporary tattoo paper and then fixed to the skin with water, similar to other temporary tattoos. A new study from Advanced Materials found that it was also possible to use adaptive printing to place lightweight “tattoos” containing electronic circuitry directly on a human hand, even if the hand is in motion. The materials are stretchable up to 30 percent, similar to human skin.

These e-tattoos can be used in wearable computing for a variety of use cases, including healthcare monitoring, location tracking, or even gaming. An individual could, in effect, turn his own hand into a smartphone controller, as shown in this video. 

What does the future hold for e-tattoos?

The Advanced Materials study’s author, Michael McAlpine, a mechanical engineering professor at the University of Minnesota, sees implications for the adaptive printing technology in the military. 

“You can think of the 3D printing tool as a Swiss Army knife for functionality,” he told Futurism, explaining that a soldier could pull the 3D printer out of a backpack and print out a biomedical device to treat an injured patient right at the scene of an accident, without waiting for emergency services.

In the healthcare field, e-tattoos are already being used to improve the state of vital signs monitoring. A new graphene-based wearable developed at the University of Texas-Austin can be attached to the skin with minimal discomfort, measuring cardiac health in two ways, both through electrocardiogram (measuring electrical activity associated with the heartbeat) and through seismocardiography (measuring vibrations in the chest associated with heartbeats). Using two sets of data helps to verify accuracy, and the device can be worn on the chest for multiple days and send data wirelessly to an application.

Consumer applications for “e-skin” are also likely: Researchers from the University of Tokyo developed a flashing display screen that could be worn directly on the back of an individual’s hand in 2016, which was functional for over 24 hours . Such a display could be used for healthcare monitoring, but also for anything from weather apps, to email, to gaming. 

Even without digital displays, wearable e-tattoos can serve as digital control panels on the body. In 2017, researchers at Saarland University in Saarbrücken, Germany conducted an experiment in which e-tattoos were placed on knuckles and on volunteers’ birthmarks and freckles. The study participants were able to easily determine how to complete desired actions, such as sliding one finger against another to adjust volume controls on a remote device.

In the future, it’s entirely possible that the majority of our wearables will be placed directly on our skin.

Chris Harrison, a researcher at Carnegie Mellon University, predicts that “you’ll have these digital tattoo parlours which you can go to in 2050, and 5 minutes later you can walk out with the iPhone 22 on your forearm.”