Huang Yonggang and John A. Rogers team, a skin electronic device that measures sweat (rate, loss and temperature) in real time Thermoregulatory disorders and diseases provide valuable physiological insights. However, obtaining accurate, continuous estimates of these parameters with high temporal resolution remains challenging. This study reports a platform that can wirelessly measure sweat rate, sweat volume and skin temperature in real time. The method incorporates short, straight fluidic channels to capture sweat flowing from the skin using a thermal actuator- and precision thermistor-based flow sensor that is physically isolated from, but thermally coupled to, sweat. The platform transmits data autonomously using an on-chip Bluetooth low energy system.
An electronic wireless system that softly attaches to the skin to analyze the kinetics and chemistry of sweat released during physical activity.
Monitoring sweat-related dynamics, such as sweat rate, accumulated sweat loss, and sweat temperature over time, can help physicians diagnose thermoregulation disorders and other heat stress-related disorders. However, there is currently no device that can measure or estimate these parameters accurately and continuously.
Professor Huang Yonggang from Northwestern University , along with researchers from John A. Rogers' team and the Korea Advanced Institute of Science and Technology, recently developed an electronic device that wirelessly measures sweat rate, sweat volume, and skin temperature. Published in a paper in Nature Electronics, the device could help monitor sweat-related dynamics more efficiently and reliably over time.
Experimental Setup and Wireless Electronics Platform, Optical Image of Experimental Setup and Wireless Platform for Bench Research.b. Exploded view, illustration of a wireless platform configured with Bluetooth Low Energy (BLE) communication.
skin interface microfluidic system designed to integrate with flow sensing platform a, the optical image shows that the sweat emerging from the forehead enters the flow sensing part in the sweat overlay and then moves to the sweat capture in the overlay /Storage section of the μ-network (a)
meandering waterways and μ-RVs separated by valves). b. Schematic diagram of the equipment.
full assembly system a, assembly drawing. b, Image of the fully assembled system mounted on the forehead of a healthy male volunteer.
John A. Rogers said: "We are developing soft microfluidic devices that attach to the skin surface that can capture, store and perform microbial marker analysis of raw proteins released through the action of the endocrine gland microliters of sweat." "Our previous research in this area, some of which was the basis for the recently launched Gatorade commercial product (see Gatorade Gx antiperspirant patch on the Gatorade website), relied on vision/image-based method to determine the extent to which sweat enters the microchannel network."
The overall goal of the recent study by Rogers and his colleagues was to develop a digital and wireless platform that could help track the so-called sweat "filling process" without the need to target Visual inspection equipment. This could be very valuable for many applications, such as tracking sweat-related processes among first responders or medical personnel, who typically wear devices under their protective gear.
"The new system we created uses a non-contact heat-based scheme to directly track sweat flow on the skin surface, eliminating the need for microchannel structures entirely, while still being compatible with more complex microfluidic systems for sweat sampling and biological Marker analysis," explained Rogers."The device continuously communicates flow and total volume information to a standard smartphone and provides information about core body temperature."
The device created by this team of researchers is designed to be applied directly to the user's skin. After collecting sweat-related information, the device automatically sends it to the smartphone via the Bluetooth low energy system.
The researchers' sensor can directly measure sweat flow and then use the collected information to quantify total sweat loss without restrictions and without the need for microchannel structures. Additionally, the device can be used in conjunction with advanced microfluidic systems or colorimetric chemistry to collect pH values and determine the concentrations of chlorine, creatinine, and glucose in the user's sweat.
In the future, an electronic platform for skin, introduced by Rogers and colleagues, could allow health professionals to more reliably collect sweat-related information in real-time. This, in turn, can aid in the timely diagnosis of multiple diseases and disorders associated with excessive sweating or disorders.
A wireless platform with skin temperature measurement capability, a circuit diagram and block diagram of the platform for multi-modal sensing of sweat rate/loss and skin temperature, and its wireless interface with a smartphone (BLE radio). The skin temperature sensing module includes a thermistor (TH); a resistance (R) at a distance of 15.5 mm from the heater. b. Pictures of the equipment. Sweat rate and skin temperature were measured under heating (top), and an upstream thermistor was placed at the inlet of the microfluidic channel (bottom) by turning. c. Sensing points on the body for multi-modal sensing of skin/sweat temperature using the device.
Rogers said: "The wireless, autonomous operation of our system enhances its usefulness and expands usage patterns to meet the needs of virtually every application from sports/fitness, worker health, medical and military use."We are now exploring commercialization opportunities as a complementary or next-generation platform for sweat analysis. "
