Long term in vivo functional stability and encapsulation reliability of using ultra-nanocrystalline diamond as an insulating coating layer for implantable microchips

at ±5 V). These results indicate that the thin coatings can effectively protect the implant from degradation in vivo. Moreover, the relationship between the surface properties of the carbon-based implants and the foreign-body response they elicit was established. Our results strongly indicate that the formation of a fibrous capsule surrounding the implants depend on the surface features of the implants (i.e., roughness, surface area, surface energy, and amount of absorbed fibrinogen) and on the amount of cytokines or chemokines secreted by the host through acute and chronic foreign-body reactions. Finally, oxygen-terminated UNCDs are promising candidates for use as encapsulating coatings without any additional surface modification or functionalization. They exhibit good bioinertness and hermeticity, thus contributing to the direct long-term protection of implantable microelectronic devices from chemical attack by bodily fluids in a physiological environment.