Researchers 3D print electronics directly on skin

University of Minnesota researchers have used a customised, low-cost 3D printer to print electronics on a real hand for the first time, in a breakthrough that could have both military and medical applications. Their groundbreaking study has been published in the journal Advanced Materials.

The 3D-printing technique uses a specialised ink made of silver flakes that can cure and conduct at room temperature — as opposed to other 3D-printing inks that need to cure at high temperatures (up to 100°C) and would burn the hand. To remove the electronics, the person can simply peel off the electronic device with tweezers or wash it off with water.

Another innovation of the 3D-printing technique is that this printer can adjust to small movements of the body during printing. Temporary markers are placed on the skin and the skin is scanned. The printer uses computer vision to adjust to movements in real time.

“No matter how hard anyone would try to stay still when using the printer on the skin, a person moves slightly and every hand is different,” said Michael McAlpine, lead author on the study. “This printer can track the hand using the markers and adjust in real time to the movements and contours of the hand, so printing of the electronics keeps its circuit shape.”

According to McAlpine, the technology could potentially be used by soldiers on the battlefield to print temporary sensors on their bodies to detect chemical or biological agents or solar cells to charge essential electronics.

“You can take your 3D printer and, if a soldier is wearing his backpack, he can just take it out of his backpack and use it to print electronic devices directly on his skin,” McAlpine said.

“It would be like a Swiss Army knife of the future, with everything they need all in one portable 3D printing tool.”

The technique is also capable of printing cells to help those with skin diseases, as demonstrated when McAlpine’s team partnered with Dr Dean Jakub Tolar, a world-renowned expert on treating rare skin disease. Together, the researchers successfully used a bioink to print cells on a mouse skin wound, which could lead to advanced medical treatments for wound healing and direct printing of grafts for skin disorders.

“We are excited about the potential of this new 3D-printing technology using a portable, lightweight printer costing less than $400,” said McAlpine.

“It is such a simple idea and has unlimited potential for important applications in the future.”

Image credit: McAlpine Group, University of Minnesota.