Get the Skinny on Drawn-On-Skin Electronics
With special inks, functional electronic components and sensors can be drawn directly on the skin.
A good deal of physical and physiological data can be obtained from sensors directly attached to human skin. This information has uses in monitoring, treating, and preventing adverse health conditions. Most wearable devices tend to have issues with poor adhesion and conformability to the attached surface that lead to undesirable motion artifacts that reduce data accuracy.
In a new advancement in the field, a team of researchers led by Cunjiang Yu at the University of Houston have developed a method to place electronic circuits and sensors directly on skin. They have given the technology a highly descriptive, straightforward name that could only be dreamed up by a group of academics that have spent an inordinate amount of time reading scientific journals — Drawn-on-Skin (DoS) electronics.
DoS electronics can track muscle signals, heart rate, temperature and skin hydration, among other physiological parameters. These drawn-on devices have the advantage of moving precisely with the skin, thereby eliminating motion artifacts. These artifacts may not be highly important with consumer-grade fitness trackers, but become crucial for diagnostic and treatment related uses. DoS electronics are also relatively simple to fabricate and do not require highly specialized or expensive equipment.
Conductive, semiconducting, and dielectric inks were created to make up the components of the circuits. Stencils giving the outline of the circuit are then created and affixed to the skin. The various inks are then applied using the stencil as a guide. The inks go on wet, then much like a traditional ink pen, quickly dry. Using the three types of inks in the proper patterns, it is possible to create transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors.
In a particularly exciting application, a DoS device designed to apply pulsed electrical stimulation was shown to accelerate wound healing in a mouse model. In the future, this technique could be used to aid patients during surgery recovery, or help soldiers on the battlefield.
The hardware hacker in me hears “transistor” and cannot help but wonder how long before DoS electronics are used to create simple digital logic circuits to add drawn-on data processing to the circuits. Using macroscopic transistors would not be especially practical for this purpose, but it does sound fun!