Offering biocompatibility and strain resistance, the new e-skin could revolutionise the development of bio-electronic devices for reliable physiological monitoring.
Recent research efforts have focused on developing flexible and soft electronics with potential applications in health monitoring, rehabilitation, and performance sports. To ensure daily wearability, these devices need to be permeable, biocompatible, and strain-resistant. Researchers at the Hong Kong Polytechnic University and other Chinese institutes have developed a new 3D integrated, flexible electronic skin that meets these criteria, as reported in Nature Electronics. The new e-skin integrates high-density inorganic electronic components with organic stretchable fibrous substrates. Traditional stretchable electronic systems often have low-density integration and rely on external printed circuit boards, which limit functionality and usability. This new e-skin uses a skin-like multilayered circuit board made of stretchable and permeable materials, including liquid metal and fiber mats.
The researchers explain that their system combines high-density components with three-dimensional patterned, multilayered liquid metal circuits and stretchable hybrid liquid metal solder. The result is an electronic skin that is soft, durable, and permeable to air and moisture, with sufficient biocompatibility for week-long on-skin attachment. The material developed is highly strain-resistant, maintaining its electrical properties up to a strain of 1,500%. It allows air and moisture to pass through, preventing rashes and skin inflammation from prolonged wear. Compared to previously developed electronic skins based on polydimethylsiloxane (PDMS), this new material is significantly thinner and less rigid.
To demonstrate its performance, the researchers created bio-electronic devices using their electronic skin. These devices can record and wirelessly transmit physiological signals to other devices. The platform enables the creation of wireless, battery-powered, and battery-free skin-attached bioelectronic systems that offer stable biosignal sensing, signal processing, analysis, electrostimulation, and wireless communication. The permeable and flexible electronic skin developed by this research team could be used to fabricate various devices for reliable and safe monitoring of physiological processes. It also has the potential to inspire the design of similar biocompatible devices using flexible circuit boards and liquid metal solders.
