The Eurostars XPatch project is developing a flexible sensor system that can monitor biochemical information from body sweat in real time. The international consortium is developing a new generation of sensory patches for competitive athletes for medical monitoring of the cardiovascular system down to the second. Fraunhofer IZM is responsible for the energy supply, communication and system integration for the flexible, self-sufficient health monitor.
Sport keeps you healthy - that's not just the case during quarantine. More and more people also want to know what the individual sports sessions are doing to their bodies, or which exercises fitness fans may not be doing themselves any favors. In the international scientific project XPatch, experts in biosensor technology are coming together to offer patches equipped with microelectronics for the fitness and medical technology market that can analyze precisely this data and display it directly on digital end devices.
But how can the patches equipped with electronics serve as fitness trackers? The small health monitor contains antennas and integrated circuits for wireless radio communication with a Bluetooth-enabled end device, a flexible micro-battery for self-sufficient energy supply, the analog electronics, the sensor chip and the power management. The microelectronics experts at the Fraunhofer Institute for Reliability and Microintegration developed the assembly and integration technology to realize thin biosensors and electronic components as flexible patches that enable practical use by athletes in everyday life. The overall system in the form of a patch, including all built-in components and functionalities, should ultimately be significantly thinner than 1 mm.
As XPatch is a biocompatible and flexible module that can be applied to the skin, soft and stretchable, but above all skin-like materials such as polyurethane and silicone were used. By embedding the electronics in skin-like materials, all components are protected from the back of the patch and do not come into direct contact with the skin. The special highlight, however, are the thin biochemical sensor chips: they are applied to the sensitive patch surface where contact with the skin is guaranteed. Sweat analysis is made possible through an opening in the substrate: a tiny piece of fleece on the free area of the plaster behind the chip is used to record body sweat. The sensors contained in the chip are intended to transmit the measured information to a terminal device in real time and thus be used to successfully improve physical fitness.
For example, the sweat of athletes can be analyzed and the measured values made directly visible to users on mobile devices. In order to send the recorded biochemical values to a smartphone via wireless transmission, Fraunhofer IZM also integrated an energy-saving wireless interface based on the Bluetooth Low Energy transmission standard into the flexible patch. The antenna required for transmitting and receiving had to be designed to be as compact as possible and at the same time meet the application requirements in terms of material, shape change and electrical properties.
Now that the ultrasensitive patch has been successfully technically validated, fully functional prototypes have been built and will be tested in direct use by sports enthusiasts from the end of August. The XPatch project is funded by the BMBF as part of the EUROSTARS program and will run until the end of 2020. The project consortium comprises project partners from four countries: Xsensio (Switzerland) deals with the lab-on-chip technology for welding analysis, R-DAS (Slovakia) is responsible for the ASIC design as well as the analog circuit design, VU Amsterdam performs physiological tests and as well as OLT (Germany) the data analysis.
Fraunhofer IZM will benefit in particular from the findings in the field of flexible substrate technologies and the integration of electronic components such as batteries and antennas for medical applications. Ideally, the technologies can be used by medical technology companies, component and material manufacturers to develop or improve their own products. The aim is to introduce new products based on the results of this project within the next five years.
