A team of scientists from the University of Minnesota has used a custom 3D printer to print electronics on human hands.
These electronic "tattoos" could be used for a number of purposes, including printing temporary sensors on soldiers to detect chemical or biological agents, or even acting as solar cells for charging critical electronic devices.
The new, low-cost technology has also been utilized to print biological cells on a mouse's skin wound, which may pave the way for direct skin graft printing out in the field.
"I'm fascinated by the idea of printing electronics or cells directly on the skin," said Michael McAlpine, the study's lead author and the University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering. "It is such a simple idea and has unlimited potential for important applications in the future."
According to McAlpine, the printed markings could become a "Swiss Army Knife" for a variety of purposes made possible through one 3D printing tool.
The 3D printing technique is different from most as it allows for the body's small movements during the process. Temporary markers are placed on the skin and the surface is scanned, while the printer uses custom software to adjust to movements in real-time, which keeps circuit designs in place.
An ink made from silver flakes which can cure at room temperature is used, which makes the direct printer-to-skin process safe and keeps hands from burning. The majority of today's 3D printers require extreme heat to cure which would ruin human skin if it was used as a surface.
The temporary "tattoo" can be removed by washing it away in water or simply peeling it off.
"We are excited about the potential of this new 3D-printing technology using a portable, lightweight printer costing less than $400," said McAlpine. "We imagine that a soldier could pull this printer out of a backpack and print a chemical sensor or other electronics they need, directly on the skin."