3D printing directly on skin

Image courtesy of McAlpine group, University of Minnesota

New 3-D printing technology that allows electronics to be printed on your skin won’t make you a cyborg but it could help soldiers detect threats such as chemical weapons.

Researchers at the University of Minnesota have successfully printed electronic circuitry on a human hand using a customized but low-cost 3-D printer.

“We’re excited about the potential of this new 3-D printing technology using a portable, lightweight printer costing less than $400,” Michael McAlpine, the study’s lead author and a professor of mechanical engineering at the University of Minnesota, said in a press statement. “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. It would be like a Swiss Army knife of the future, with everything they need all in one portable 3-D printing tool.”

Other possible applications include printing solar cells on sun-exposed skin to charge electronic devices.

“It’s such a simple idea and has unlimited potential for important applications in the future,” said McAlpine.

The research was published in the journal Advanced Materials.

One expert said the prospects of such technology are intriguing.

“One might question the need to print a chemical detector on the skin versus having an external sensor that detects chemical weapons,” Terry Wohlers, president of Wohlers Associates Inc., a consulting firm in Colorado that provides technical and strategic consulting on 3-D printing, told Healthline. “Even so, the possibility is interesting.”

“The mainstream use of 3-D printed electronics onto or inside living tissue is likely years away, but it gives us a view of what the future of 3-D printing might look like,” added Wohlers. “I could foresee the printing of sensors on animals for the beef industry or onto pets for tracking purposes. When you begin to consider the possibilities, they become almost limitless.”

The University of Minnesota researchers also printed biological cells directly onto a skin wound on a lab mouse in a parallel experiment. This could have implications for treating wounds or printing grafts for skin disorders.

How it works

One of the challenges of printing on skin is adjusting for small movements while printing’s in progress.

McAlpine and colleagues placed markers on the skin that the printer used as reference points.

“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,” said McAlpine.

The printer also used special ink made of silver flakes. Unlike other 3-D printer inks, this silver ink can cure and conduct electricity at room temperature.

The skin circuitry is temporary and can be easily peeled or washed off when no longer needed, researchers said.

3-D printing advancements

The University of Minnesota research is just the latest advance in the use of 3-D printing on human skin.

In January 2017, scientists from the Universidad Carlos III de Madrid, Spain’s Center for Energy, Environmental and Technological Research, and Hospital General Universitario Gregorio Marañón unveiled a prototype 3-D bioprinter to produce functional human skin using biologically based ink.

“This skin is adequate for transplanting to patients or for use in research or the testing of cosmetic, chemical, and pharmaceutical products,” according to a press statement.

Last month, University of Toronto researchers launched a working model of a 3-D skin printer designed for skin grafts.

The U.S. National Institutes of Health awarded a $6.25 million grant to Rice University, the University of Maryland, and Wake Forest University to establish the Center for Engineering Complex Tissues in 2017. University of Maryland researchers are spearheading research on 3-D printed bioreactors used to produce large quantities of stem cells and other cell cultures.

“3-D printing is being researched for use across the medical industry from printing sugar scaffolds for growing organs to 3-D printed cornea replacements,” Matt Stultz, digital fabrication editor for Maker Media in San Francisco, told Healthline. “3-D printed prosthetic devices and implants are becoming more and more common and will likely become the standard, since you can create a device for a person instead of trying to fit a standard device to a person it may not fit.”