An innovative microfluidic skin patch has been developed by a research team at Northwestern University that is capable of monitoring the health of patients during exercise by analyzing their sweat. The gadget has potential to provide detailed information during exercise on a level that has not been possible with current wearable devices.
While fitness trackers and other wearable devices can monitor heart rate and other health metrics, the microfluidic skin patch offers “clinical-like precision measurement of health markers,” according to John Rogers, Professor of Materials Science and Engineering, Biomedical Engineering and Neurological Surgery at the Louis Simpson and Kimberly Querrey Biomedical Research Center of Northwestern University’s McCormick School of Engineering.
Sweat contains a range of biomedical markers that can provide detailed physiological information about an individual’s current state of health; however, conducting a sweat analysis during exercise is no easy task. However, the researchers have created a device that can be comfortably worn against the skin during exercise which serves as a mobile sweat analysis lab.
The patch contains a network of microfluidic channels and storage reservoirs where a biofluid analysis takes place. In contrast to other wearable fitness and health devices, the microfluidic skin patch requires no power source. The reservoirs can store sweat for around 125 hours after removal from the skin if the device is sealed and for around 75 hours without sealing.
The microfluidic skin patch can be paired with a smartphone to provide timely information to the wearer. When a paired smartphone is placed in close proximity to the device, the electronics in the patch trigger the app to take a photo of the device.
The app then performs a colorimetric analysis of the patch to determine concentrations of lactate, chloride, glucose, and pH. The app will then issue alerts – if hydration is required for instance. The patch can be used to monitor sweat rate and loss and will collect and store sweat for later lab analysis.
The team has just completed the all-important first phase of field testing to ensure the patch functioned as intended and remained on the skin during heavy exercise in tough conditions: The 104km El Tour de Tucson bike race through the Arizona desert. Previously, the skin patch had only been tested during an indoor cycling trial.
The team reports that the patch stayed in place during the grueling and sweaty race and continued to function as expected. The patch can be used only once, but since it is relatively cheap to manufacturer the team believe there is considerable commercial potential. The goal is now to reduce the cost of the patch to around $1-$2.
The patch has already attracted considerable interest from a range of companies including L’Oréal, as well as the U.S. military. The patch also has potential to be developed further to be used as an effective tool for disease diagnosis, potentially offering physicians the option for performing a bloodless prescreening test for diabetes. The patch already detects a biomarker in human sweat that is linked to cystic fibrosis.