Development of Stable Long‐term Electrode Tissue Interfaces for Recording and Stimulation

Brain Computer interfaces (BCIs) are stable inside the brain over long periods of time and that have minimal effects on the physiological conditions of the neural tissue. This chapter reviews the state-of-the-art of neural interfaces and the concepts behind recent research and development of biocompatible BCIs. It focuses on various tissue responses in the brain to an implanted foreign body. A number of implantable micro-electrode arrays have been developed for use as neural interfaces for BCIs. The chapter then focuses on how to minimize the foreign body reactions and loss of neurons around the implant that has resulted in identification of several key features that electrodes need to fulfill and the development of novel ultra-thin/elastic and flexible constructs that fulfill these requirements. By using hard but dissolvable matrix materials, arrays of ultra-flexible electrodes can be implanted. Importantly, gelatin-based embedding materials also appear to protect the neurons close to the BCI.