Bioink Composition and Printing Parameters for 3D Modeling Neural Tissue.

Neurodegenerative diseases (NDs) are a broad class of pathologies characterized by the progressive loss of neurons in the central nervous system. The main problem in the study of NDs is the lack of an adequate realistic experimental model to study the pathogenic mechanisms. Induced pluripotent stem cells (iPSCs) partially overcome the problem, with their capability to differentiate into almost every cell types; even so, these cells alone are not sufficient to unveil the mechanisms underlying NDs. 3D bioprinting allows to control the distribution of cells such as neurons, leading to the creation of a realistic in vitro model. In this work, we analyzed two biomaterials: sodium alginate and gelatin, and three different cell types: a neuroblastoma cell line (SH-SY5Y), iPSCs, and neural stem cells. All cells were encapsulated inside the bioink, printed and cultivated for at least seven days; they all presented good viability. We also evaluated the maintenance of the printed shape, opening the possibility to obtain a reliable in vitro neural tissue combining 3D bioprinting and iPSCs technology, optimizing the study of the degenerative processes that are still widely unknown.