Wearable electronic devices for health monitoring using electronic skin have emerged but most electronic skin-related technologies utilize materials such as plastic or rubber that can cause skin irritation or interfere with metabolism when attached to skin or biological tissue.
When these devices are attached to the skin for a long duration, they are impermeable to oxygen and can cause skin irritation such as itching and eczema. This makes it difficult to precisely and chronologically analyze and treat the biometric information of users who exercise without constraint.
A new electronic skin was developed that offers several improvements over existing trackers, including greater flexibility, smaller size, and the ability to stick the self-adhesive patch — a very soft silicone about 1.5” in diameter — just about anywhere on the body. The electronic skin uses nanofiber substrates that are permeable to oxygen, perspiration, and other bodily fluids, making the skin useful for long-term health monitoring because it does not cause discomfort or inflammation to the body.
The substrate incorporates one-dimensional nanofibers rather than the conventional two-dimensional planar substrate. A technique was applied to develop electronic skin devices on the substrate. Bio-signals such as body temperature and electromyogram (EMG) can also be collected.
The electronic skin contains about 50 components connected by a network of 250 tiny wire coils embedded in protective silicone. The soft material enables it to conform to the body, unlike other hard monitors. It wirelessly transmits data on movement and respiration, as well as electrical activity in the heart, muscles, eyes, and brain to a smartphone application.
Unlike flat sensors, the tiny wire coils in this device are three-dimensional, which maximizes flexibility. The coils can stretch and contract like a spring without breaking. The coils and sensor components are also configured in an unusual spider web pattern that ensures uniform and extreme levels of stretchability and bendability in any direction. It also enables tighter packing of components, minimizing size.
The nanomesh conductors are nano-sized fiber substrates made by coating water-soluble, high-molecular polyvinyl alcohol (PVA) with gold particles. On top of that, utilizing conventional electronic skin technology, a sensor can measure touch, temperature, pressure, and other health data.
The nanofiber-based electronic skin has excellent adhesion even when attached to joints such as fingers. Also, it has a structure that can circulate air and bodily fluids through nano-sized holes uniformly distributed throughout the substrate. In addition, it is thinner and softer compared to existing electronic skin, and can be attached with water without using any separate adhesive. This way, users can directly attach the skin to the desired part of the body.