Development of an extrusion-based 3D-printing strategy for clustering of human neural progenitor cells

3D bioprinting offers a simplified solution for the engineering of complex tissue parts for in-vitro drug discovery or, in-vivo implantation. However, significant amount of challenges exist in 3D bioprinting of neural tissues, as these are sensitive cell types to handle via extrusion bioprinting techniques. We assessed the feasibility of bioprinting human neural progenitor cells (NPCs) in 3D hydrogel lattices using a fibrinogen-alginate-chitosan bioink, previously optimized for neural-cell growth, and subsequently modified for structural support during extrusion printing, in this study. The original bioink used in this study was made by adding optimized amounts of high- and medium-viscosity alginate to the fibrinogen-chitosan-based bioink and making it extrudable under shear pressure. The mechanically robust 3D constructs promoted NPC cluster formation and maintained their morphology and viability during the entire culture period. This strategy may be useful for co-culturing of NPCs along with other cell types such as cardiac, vascular, and other cells during 3D bioprinting.