SafeTouch

The spread of pathogens via frequently touched surfaces poses a major challenge worldwide, particularly in sensitive areas such as hospitals or public facilities. As part of the EU-funded SafeTouch project, Fraunhofer ISIT is working with European partners to develop a novel solution for the automatic disinfection of such contact surfaces. At its heart is an innovative chip whose surface is heated to a high temperature within fractions of a second, thereby reliably killing germs. The technology enables fast, chemical-free and energy-efficient cleaning – immediately after every touch.

At the heart of SafeTouch is a microelectronic chip that can be integrated into surfaces such as door handles, lift buttons or light switches. A brief electrical pulse heats the chip’s surface to around 130 °C. At this temperature, viruses are immediately inactivated and bacteria killed. Immediately afterwards, the surface cools down again, meaning the entire cleaning cycle takes just a few tenths of a second.

A key advantage over conventional disinfection methods lies in the combination of speed, efficiency and safety. Traditional methods are often time-consuming, costly, chemical-based or not consistently reliable. SafeTouch, on the other hand, operates automatically, requires no additional cleaning agents and can work continuously in the background. Despite the high local temperature, the application remains safe for humans: the amount of heat stored in the chip and transferred to the skin is so low that no skin damage is to be expected, even with brief contact during heating. This is made possible by the specific design of the thermal mass. The surface of the chip heats up quickly, but releases only minimal energy to the skin.

Technologically, the chip is based on a flexible glass substrate that acts as both an electrical and thermal insulator. A metallic layer serves as a heating element, whilst a special epoxy resin coating protects the underlying structures and provides a robust, abrasion-resistant surface. The flexibility of the substrate is particularly crucial for curved applications, such as door handles.

The development of SafeTouch requires a high degree of interdisciplinary collaboration. Fraunhofer ISIT plays a central role in the process development and manufacture of the chips. One of the biggest challenges lies in integrating new manufacturing technologies, such as those for flexible glass wafers and so-called through-glass vias (TGVs), which enable electrical connections through the substrate. Particular attention is paid to material processing: for example, a chemical glass hardening process must take place early in the manufacturing sequence to achieve the desired flexibility, yet this simultaneously restricts subsequent processing steps. The combination of different materials and processes, such as in the metallisation or laser processing of entire wafers, also requires innovative solutions.

The project is coordinated by the National Technical University of Athens (NTUA), which is responsible not only for the development of the electronics but also for testing and chip design. Other partners are taking on specialised tasks: A4TEC and Biogipuzkoa are conducting biological tests on efficacy and biocompatibility, whilst organisations such as the Hellenic Biocluster and Martel Innovate are supporting commercialisation, communication and project management. The consortium is complemented by partners specialising in sustainability assessment, application testing and innovation management.

In addition to the immediate benefits for infection prevention, SafeTouch also opens up new technological perspectives. The developed processes make it possible to implement functional structures on flexible glass substrates and to control them electrically. This could in the future find application in areas such as flexible MEMS systems or high-frequency electronics.  

With SafeTouch, Fraunhofer ISIT makes an important contribution to improving public health while also demonstrating how microelectronic innovations can address concrete societal challenges. The project is an exemplary case of the successful transfer of research into practical solutions and of the strength of European collaboration in cutting-edge technology.