Differentiation of motor neurons from iPSC- derived neural progenitors in 3D printed bioscaffolds

Journal article, 2025

Translational medicine for neurodegenerative diseases can advance through the use of in vitro models incorporating human neural cells derived from patient-specific induced pluripotent stem cells (iPSCs). Previously, we investigated whether motor neuron (MN) progenitors derived from human iPSCs could differentiate to MNs within 3D-printed scaffolds. While extensive neurite arborization was observed on the scaffold surface, no neurite outgrowth occurred within the scaffold interior. Here we show the extensive growth of the neurites from iPSC-derived neural progenitors, imbedded into the gelatin scaffolds during 30 days of experimental time. We present a bioink formulation that softens the scaffold while preserving its 3D structure, thereby facilitating neurite outgrowth throughout the scaffold. MN differentiation, evidenced by extensive neurite arborization and the expression of choline acetyltransferase (ChAT) was verified in 3D images deep within the scaffold structure. Notably, the degree of MN differentiation appeared to depend on two factors: the delivery of MN differentiation factors via mesoporous silica particles (MSPs) embedded in the bioink and the method used to generate MN progenitors prior to 3D printing. We provide a detailed protocol for 3D printing human iPSC-derived MN progenitors, enabling their differentiation and survival within gelatin scaffolds. This protocol could be expanded to incorporate additional cell types, allowing the creation of more complex and standardized 3D neural tissues. Such advancements could facilitate investigations into the pathophysiology of motor neuron diseases and the development of new therapeutic strategies.