3D Printing of Neural Tissues Derived from Human Induced Pluripotent Stem Cells Using a Fibrin-Based Bioink.

3D bioprinting offers the opportunity to automate the process of tissue engineering, which combines biomaterial scaffolds and cells to generate substitutes for diseased or damaged tissues. These bioprinting methods construct tissue replacements by positioning cells encapsulated in bioinks into specific locations in the resulting constructs. Human induced pluripotent stem cells (hiPSCs) serve as an important tool when engineering neural tissues. These cells can be expanded indefinitely and differentiated into the cell types found in the central nervous systems, including neurons. One common method for differentiating hiPSCs into neural tissue requires the formation of aggregates inside of defined diameter microwells cultured in chemically defined media. However, 3D bioprinting of such hiPSC-derived aggregates has not been previously reported in the literature, as it requires the development of specialized bioinks for supporting cell survival and differentiation into mature neural phenotypes. Here we detail methods including preparing base material components of the bioink, producing the bioink, and the steps involved in printing 3D neural tissues derived from hiPSC-derived neural aggregates using Aspect Biosystems' novel RX1 printer and their lab-on-a-printer (LOP) technology.