In-vivo implantable electronic devices such as cardiac pacemakers and cochlear implants are made of hard materials such as silicon, but research and development of highly flexible organic materials is underway to improve compatibility with living organisms. Has been done.However, it has been difficult to implant the device in the living body for a long period of time and stably measure the biological signal due to the protective functions such as rejection reaction and inflammatory reaction in the living body.

　This time, the research group created a new gel material by uniformly mixing single-walled carbon nanotubes with a hydrogel called polyrotaxane.By using the technology to unravel carbon nanotubes with ionic liquid, the nanotubes are evenly dispersed in the gel, and the gel is successfully made conductive.Next, in order to evaluate the biocompatibility of this new gel material, a XNUMX-week in-vivo implantation test was carried out, and it was confirmed that the material had an extremely small inflammatory reaction.Furthermore, by integrating this gel electrode and the amplifier circuit of the organic transistor manufactured on the ultra-thin polymer film, a sheet-type biopotential sensor with excellent biocompatibility was realized.By attaching this sensor to the heart of a rat with heart disease and measuring abnormal and normal electrocardiography due to ischemia, the site of myocardial infarction was accurately identified.In particular, the amplifier circuit has greatly improved the signal-to-noise ratio.

　In the future, by implanting this sheet-type bioelectric potential sensor in the body for a long period of time, it is expected to have various applications as a next-generation medical device, such as early detection of diseases and utilization for treatment.