Researchers in the Cockrell School of Engineering at the University of Texas at Austin have developed a new a method for producing inexpensive and high-performing wearable patches that can continuously monitor the human body’s vital signs.
Assistant Professor Nanshu Lu and her team believe the new wearable patch is ideal for human health and performance tracking, and could potentially outperform traditional monitoring tools such as cardiac event monitors.
The new wearable patch has the ability to pick up and transmit the human body’s vital signals, tracking heart rate, hydration level, muscle movement, temperature and brain activity.
The researcher’s manufacturing method aims to construct disposable ultrathin tattoo-like health monitoring patches for the mass production of epidermal electronics, a popular technology that Lu helped develop in 2011.
The team’s repeatable “cut-and-paste” method for making epidermal electronics has cut manufacturing time from several days to only 20 minutes. They believe their new method is compatible with roll-to-roll manufacturing — an existing method for creating devices in bulk using a roll of flexible plastic and a processing machine.
“One of the most attractive aspects of epidermal electronics is their ability to be disposable,” said Lu. “If you can make them inexpensively, say for $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.”
The UT Austin method is the first dry and portable process for producing these electronics and, 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 3D 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. Then 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.
“These initial prototype patches can be adapted to roll-to-roll manufacturing that can reduce the cost significantly for mass production,” said Associate Professor and materials expert in the Cockrell School, Deji Akinwande. “In this light, Lu’s invention represents a major advancement for the mHealth industry.”
After producing the cut-and-pasted patches, the researchers tested them as part of their study. During the test, the wearable patches picked up body signals that were stronger than those taken by existing medical devices, including an ECG/EKG. The team also found that their patch conforms almost perfectly to the skin, minimizing motion-induced false signals or errors.
Due to the high sensitivity of the wearable patches, Lu and her team can envision humans wearing the patches to more easily manoeuvre a prosthetic hand or limb using muscle signals. “But for now we are trying to add more types of sensors including blood pressure and oxygen saturation monitors to the low-cost patch,” concluded Lu.