New method leads to cheaper wearable electronic health patches

Researchers have developed a method for producing inexpensive and high-performing wearable patches that can continuously monitor the body's vital signs.
The research led by Assistant Professor Nanshu Lu in the Cockrell School of Engineering at The University of Texas at Austin aims to construct disposable tattoo-like health monitoring patches for the mass production of epidermal electronics, a popular technology that Lu helped develop in 2011.
The team has developed a repeatable "cut-and-paste" method for making epidermal electronics that cuts manufacturing time from several days to only 20 minutes.
Reliable, ultrathin wearable electronic devices that stick to the skin like a temporary tattoo are a relatively new innovation.

These devices have the ability to pick up and transmit the human body's vital signals, tracking heart rate, hydration level, muscle movement, temperature and brain activity.
Although it is a promising invention, a lengthy, tedious and costly production process has until now hampered these wearables' potential.

"One of the most attractive aspects of epidermal electronics is their ability to be disposable," Lu said.
"If you can make them inexpensively, say for USD 1, then more people will be able to use them more frequently. This will open the door for a number of mobile medical applications and beyond," Lu added.

The UT Austin method is the first dry and portable process for producing these electronics, which, unlike the current method, does not require a clean room, wafers and other expensive resources and equipment.
Instead, the technique relies on freeform manufacturing, which is similar in scope to 3-D printing but different in that material is removed instead of added.
The two-step process starts with inexpensive, pre-fabricated, industrial-quality metal deposited on polymer sheets. First, an electronic mechanical cutter is used to form patterns on the metal-polymer sheets.
Second, after removing excessive areas, the electronics are printed onto any polymer adhesives, including temporary tattoo films. The cutter is programmable so the size of the patch and pattern can be easily customised.

After producing the cut-and-pasted patches, the researchers tested them as part of their study.
In each test, the researchers' newly fabricated patches picked up body signals that were stronger than those taken by existing medical devices, including an ECG/EKG, a tool used to assess the electrical and muscular function of the heart.
The team also found that their patch conforms almost perfectly to the skin, minimising motion-induced false signals or errors.
The research was published in the journal Advanced Materials.