Figure 1.

In vitro CNS models. (A) Confocal micrographs showing 2D-hippocampal dissociated cultures, immunostained for the cytoskeletal component β-tubulin III (in red), the glial protein GFAP (in green) and DAPI to visualize neurons (in blue). Scale bar = 100 µm. Modified from Barrejón et al. (2019) with permission. (B) Light micrograph of a hippocampal slice [modified from Miller et al. (2015) with permission]. (C) Confocal section and 120-µm thick 3D stacks reconstruction showing a 3D hydrogel-encapsulated cortical neuronal network, immunostained for neurons (red, β-tubulin III), glia (green, S100) and nuclei (blue, DAPI). Scale bar = 50 µm [modified from Dana et al. (2014) with permission]. (D) Confocal image representing neurosphere processed for immunofluorescence against Arl13b (red) and DNA [modified from Shimada et al. (2017) with permission]. (E) A representative image of an organoid immunostained for neurons (TUJ1, green) and progenitors (SOX2, red) [modified from Lancaster and Knoblich (2014) with permission]. (F) Schematic image of a microfluidic device where vascular and neuronal networks were co-cultured [modified from Osaki et al. (2018b) with permission]. (G) Schematic representation of in vivo and in vitro cortical brain layer structures, in which each colour represents a different printed layer. In the bottom panel, confocal reconstructions of the neurons coloured for their z-axis distribution through the gel after 5 days of culture. Scale bar = 100 µm [modified from Lozano et al. (2015) with permission]. (H) Schematic sketch of a potential 3D-printing procedure to generate a mini-brain from cellular spheroids [modified from Han and Hsu (2017) with permission].