Advancements in Flexible Electrode Implantation for Invasive Brain-Computer Interfaces

In recent years, with the development of flexible electronic devices and advances in material science, flexible electrodes have played an important role in the field of invasive brain-computer interface (BCI). Compared with traditional rigid electrodes, flexible electrodes implanted in the brain cause less damage to brain tissue and are more biocompatible and stable. Most of the traditional invasive electrodes are made of glass or metal, which are prone to brain tissue damage, inflammation, and other problems, although they can avoid interference from the skull and skin and record neural signals accurately and with low noise. However, the main materials for flexible electrodes are polymers, hydrogels, graphene, etc., which can reduce immune rejection and prolong the service life of neural implants. This paper describes five main implantation methods for flexible electrodes in recent years: microneedle arrays, coiled implantation, minimally invasive injections, biodegradable electrodes, and stretchable electronics implantation. They can be used in the most appropriate way for electrodes of different structures to acquire neural signals with stable and reliable fidelity. Flexible electrodes have the potential for a wide range of applications in neuromonitoring providing a safer and more durable solution for invasive brain-computer interfaces. Then the authors will propose a new idea combining their respective advantages in the hope of bringing enlightenment.