Wearable and implantable devices are being developed to collect various biometric data for health monitoring and disease management. However, due to the rigidity of electronic circuits and the thickness of their substrates, conventional devices often cause discomfort and struggle to maintain close contact with the skin. This challenge is especially pronounced when attaching or implanting devices to highly sensitive and flexible areas like the palm or sole.
Kento Yamagishi, a lecturer at the University of Tokyo's Graduate School of Engineering, has developed an "ultra-thin electronics film" by mounting and printing electrodes, wiring, and antennas onto an ultra-thin polymer film with a thickness ranging from several hundred nanometers (a billionth of a meter) to several micrometers (a millionth of a meter), giving it electronic functionality. This film is more than 100 times thinner than conventional thin-film devices, allowing it to be attached to the skin or organs like a sticker.
One potential application of this ultra-thin electronic film is in the motion analysis of athletes. Yamagishi's team developed an ultra-thin electrode with a thickness of about 300 nm to measure the electromyographic potential on the surface of the palm during a baseball throw. Yamagishi refers to this as an "electronic nano bandage." This electronic nano bandage can adhere directly to the skin surface without the need for additional adhesives. The technology could also be applied to healthcare devices for infants, the elderly, or individuals with disabilities, as well as to bioelectrodes for prosthetic hands or feet.
Another application is in phototherapy for cancer. In a treatment method called photodynamic therapy (PDT), photosensitizing agents are administered to cancerous tissue and then exposedd to light, generating reactive oxygen species that target and destroy cancer cells. For PDT to be effective, it is essential to position the light precisely over the cancer tissue, as even slight misalignment can render the treatment ineffective. Yamagishi combined his tissue-adhesive, rubber-based ultra-thin film with a wireless-powered LED to develop a light-emitting device that can be attached like a sticker to the surface of cancer tissue. In collaboration with physicians, the team demonstrated the effectiveness of a world-first implantable PDT system in cancerous mice.
While thin-film-based flexible electronic devices are attracting significant attention, Yamagishi's ultra-thin electronics stand out for their remarkable thinness, flexibility, and ease of attachment. This technology is expected to have applications not only in medicine but also across a wide range of other fields.
