Flexible electronics have the potential to help monitor, and even modulate, a number of physiological parameters. While stick-on heart monitors can be manufactured as one-size-fits-all, in applications such as electronic bandages that can monitor and treat a wound, it’s best to be able to create custom devices that suit each patient’s needs.

Currently, making flexible electronics requires harsh processing, including chemical baths, hardening processes, and high temperature baking to purify the materials being used. Now, researchers at Duke University have come up with a way to directly print functional flexible electronics directly onto the skin, paper, bandages, and other flexible and moving devices. The capability may allow clinicians to print diagnostic and therapeutic devices right onto patients or onto bespoke medical tools.

“When people hear the term ‘printed electronics,’ the expectation is that a person loads a substrate and the designs for an electronic circuit into a printer and, some reasonable time later, removes a fully functional electronic circuit,” said Aaron Franklin, one of the lead researchers, in a Duke press release. “Over the years there have been a slew of research papers promising these kinds of ‘fully printed electronics,’ but the reality is that the process actually involves taking the sample out multiple times to bake it, wash it or spin-coat materials onto it,” Franklin said. “Ours is the first where the reality matches the public perception.”

The capability is possible thanks to two new advances. One is a new silver nanowire conductive ink. It can be printed at low temperatures and doesn’t need additional processing. It maintains conductivity even after it is bent back and forth thousands of times. The other advancement is to use the same ink along with carbon nanotubes to create electronic transistors directly on a surface, which also does not involve any harsh processing. The silver nanowire ink and new transistors provide the main components of an electronic system.