Enhancing biocompatibility of the brain-machine interface: A review

In vivo implantation of microelectrodes opens the door to studying neural circuits and restoring damaged neural pathways through direct electrical stimulation and recording. Although some neuroprostheses have achieved clinical success, electrode material properties, inflammatory response, and glial scar formation at the electrode-tissue interfaces affect performance and sustainability. Those challenges can be addressed by improving some of the materials' mechanical, physical, chemical, and electrical properties. This paper reviews materials and designs of current microelectrodes and discusses perspectives to advance neuroprosthetics performance. • Biocompatible coatings can promote long-term electrode coatings. • Pharmaceutical, peptide, and polymer coatings reduce inflammatory responses in implantable electrodes. • Mechanical, thermal, and electrical properties affect chronic microelectrode array stability. • Implantable electrodes activate immune response and promote glial scar formation.