Microelectrode coatings for neural stimulation and recording

The use of electro-active coatings at charge-injection and recording sites on microelectrodes for central nervous system prostheses is reviewed. Iridium oxide is the most extensively evaluated coating and its performance is compared with noble metals and other candidate coatings. Charge-injection mechanisms are contrasted and charge-injection limits for different electrode materials given. Even though, iridium oxide appears the most promising coating for neural applications, our knowledge of the stability of iridium oxide, particularly from in vivo assessments, is limited.