http://www.digitaljournal.com/tech-and-science/technology/3-d-electronics-printed-directly-onto-skin/article/520987

3D electronics printed directly onto skin

Posted Apr 29, 2018 by Tim Sandle
3D print electronics and cells can be printed directly on skin, through new technology. This could help soldiers on the battlefield and people with skin disorders.
The friendly new electrode is comfortable and accessible  allowing users to carry on as usual with t...
The friendly new electrode is comfortable and accessible, allowing users to carry on as usual with their daily routines, while monitoring their muscle activity for many hours, for a range of medical and other purposes.
Prof. Yael Hanein, Tel Aviv University
Scientists from the University of Minnesota have used a customized, low-cost 3D printer in order to print electronics directly onto a human hand for the first time. This type of technology could be used to print temporary sensors onto bodies so that chemical or biological agents could be detected. Alternatively, solar cells could be printed onto skin to charge essential electronics.
Essential to the development was with designing the printer so that it deploys computer vision to track and adjust to movements in real-time. To trial out the development, the scientists succeeded in printing biological cells on the skin wound of a mouse. The printer that was adapted cost less than $400.
As well as military applications, enabling soldiers to have an early warning system for chemical attacks, the printing method could lead to the development of new medical treatments for wound healing. Here the technology could be used for the direct printing of grafts for skin disorders.
The researchers have experimented with different inks, such as specialized ink made of silver flakes. This type of ink can cure and conduct at room temperature. This had an advantage of conventional inks used for 3D printers, which require high temperatures for operation. This means more sensitive inks can be used which will help with certain types of connected wearable technologies.
Outlining the possibilities further, lead scientist Michael McAlpine said: "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 3D printing tool."
McAlpine explains more in the following video:
The research has been published in the journal Advanced Materials, and the paper is headed "3D Printed Functional and Biological Materials on Moving Freeform Surfaces."