Conductive-Hydrogel-Based Electrodes for Invasive Neural Interfaces

Currently, technologies based on the use of electrode systems implanted in the head interacting with the human brain are under active development. Such systems are used both for stimulation of the brain in various diseases and as full-fledged neural interfaces. Electrodes in this case are one of the key elements, since they provide contact with the nervous tissue. Recently, considerable attention has been paid to polymer electrodes and, in particular, hydrogels due to the fact that they have mechanical properties close to body tissues and can carry various functional molecules. At the same time, the electrical conductivity of polymer electrodes is lower than that of metal or carbon materials. In this regard, this work provides an overview of publications in this area and notes the most promising trends. Also, based on the publications reviewed, it is noted that an important task for such electrodes remains their miniaturization. It is concluded that despite their shortcomings, electrodes based on polymer hydrogels are an extremely promising system for creating invasive neural interfaces.