3D Printing of Layered Gradient Pore Structure of Brain-like Tissue.

The pathological research and drug development of brain diseases require appropriate brain models. Given the complex, layered structure of the cerebral cortex, as well as the constraints on the medical ethics and the inaccuracy of animal models, it is necessary to construct a brain-like model . In this study, we designed and built integrated three-dimensional (3D) printing equipment for cell printing/culture, which can guarantee cell viability in the printing process and provide the equipment foundation for manufacturing the layered structures with gradient distribution of pore size. Based on this printing equipment, to achieve the purpose of printing the layered structures with multiple materials, we conducted research on the performance of bio-inks with different compositions and optimized the printing process. By extruding and stacking materials, we can print the layered structure with the uniform distribution of cells and the gradient distribution of pore sizes. Finally, we can accurately print a structure with 30 layers. The line width (resolution) of the printed monolayer structure was about 478 mm, the forming accuracy can reach 97.24%, and the viability of cells in the printed structure is as high as 94.5%.