Neural interfaces engineered via micro- and nanostructured coatings

During the past decade, neural interfaces have attracted great interest due to their potential of body-machine communication for disease diagnosis and therapy. Considering the significant material mismatch between the electrode implants and the native tissue, a thin coating is employed on the electrode sites as an intermediate layer to bridge the material differences and has been proved to play an important role in the promotion of neural cell attachment and signal transmission. Micro- and nanostructured coating materials, together with surface functionalization such as biological cues, provide not only high surface areas for signal transduction but also a biomimetic platform for the cells. In this paper, we review the performance of different kinds of micro- and nanostructured coating materials including metallic materials, carbon materials, conducting polymeric materials and composite materials and then complement the discussion with the influence of the fabrication process on the performance of the coatings. The coating could be functionalized by various advanced techniques, which are also reviewed. The existing challenge and future research directions of electrode coatings are briefly discussed at the end of the review.