Figure 18.

Bioprinting of neural structures and nerve guides. (A) Schematic diagram of the 3D bioprinting process of a neural scaffold. (B, C) SEM images of (top) PEG-DA scaffolds with large porosity of 66% fabricated by stereolithography-based bioprinting, (middle) electrospun PCL fibers attached to the bioprinted PEG-DA scaffold, and (bottom) electrospun PCL/gelatin fibers attached to the bioprinted PEG-DA scaffold. Reproduced with permission from ref.^[223]. (D, E) 3D-bioprinted brain like structures made of gellan-gum-RGD: (D cortical neurons incorporated into hydrogels of different concentration stained with ßIII tubulin (red) for cortical neurons and DAPI (blue) for nuclei; (E) confocal images of neurons, where the different colors represent the depth of the neurons from 0 μm (blue) to 60 μm (red). Reproduced with permission from ref.^[221]. (F) Fluorescence micrograph showing the repair of a peripheral nerve supported by a 3D-bioprinted nerve guide made of PEG after implantation into mice with an induced small gap nerve injury. Different pseudo-colors represent individually tracked axons that displayed re-connection at 21 days post-implantation. Reproduced with permission from ref.^[222].