Figure 2.

Materials strategies to improve biocompatibility. (a) Left: a micro-computed tomography (CT) scan of an implanted nanoelectronic thread (NET) array in a rat brain consisting of eight 128-channel modules (1024 channels in total) at a high 3D density. The purple cube highlights the NET array. Right: schematics of the 3D NET array embedded in cortical tissues. (b) Micro-CT scan showing the volumetric distribution of an 8 × 8 × 16 (1024-channel) NET array in a mouse visual cortex. (a, b) Adapted with permission from Reference 17. (c) Optical image of an implant and scanning electron micrographs of the gold film and platinum-silicone composite. (d) Heat maps and bar plots showing normalized astrocyte and microglia density. (c, d) Adapted with permission from Reference 18. (e) Schematic showing the fabrication of nano-conductive gels (CGs) and microCGs. An alginate solution, graphite felts (GFs), and/or carbon nanotubes (CNTs) were mixed and immediately cross-linked to create the nanoCGs (top). When the mixed solution was frozen and lyophilized before cross-linking, microCGs were formed with a higher density of carbon additives in the gel walls (bottom). RT, room temperature. (f) Schematic of the proposed device and its various components. (e, f) Adapted with permission from Reference 19. (g) Glial fibrillary acid protein (GFAP) immunofluorescence as a function of distance from the electrode/biotic interface compared to uncoated controls eight weeks after implantation. (h) GFAP immunolabeling observed in normal rat cortical tissue at the same level as the implant site (left), at the uncoated microelectrode interface (middle) and at the microelectrode astrocyte-derived extracellular matrix (ECM)-coated interface (right) eight weeks after implantation. Scale bar = 10 pm. (g, h) Adapted with permission from Reference 20.