To develop effective drugs for various neurological diseases such as Alzheimer’s, it is important to build an accurate model of the architecture of the brain and its biochemical reactions. The common procedure for this process is to create and grow these models on petri-dishes. However, these dishes do not allow the cells to interact with each other properly as they would do in the 3D natural brain environment. We have made a 3D cellular environment using 3D bioprinting and a composite of biofriendly engineered gels to create a brain-like construct patterned with neural cells. We show that the cells embedded in these printed mini brains can grow and form neurons and other brain cells and interact with their neighboring cells in 3D. The materials and printing method can be tuned to capture different stiffnesses, patterns and cellular interactions. In the future, these constructs can be further engineered into a reproducible platform for modeling neurological diseases and drug testing.
A crucial step in creating reliable in vitro platforms for neural development and disorder studies is the reproduction of the multicellular three-dimensional (3D) brain microenvironment and the capturing of cell-cell interactions within the model. The power of self-organization of diverse cell types into brain spheroids could be harnessed to study mechanisms underlying brain development trajectory and diseases. A challenge of current 3D organoid and spheroid models grown in petri-dishes is the lack of control over cellular localization and diversity. To overcome this limitation, neural spheroids can be patterned into customizable 3D structures using microfabrication. We developed a 3D brain-like co-culture construct using embedded 3D bioprinting as a flexible solution for composing heterogenous neural populations with neurospheroids and glia. Specifically, neurospheroid-laden free-standing 3D structures were fabricated in an engineered astrocyte-laden support bath resembling a neural stem cell niche environment. A photo-crosslinkable bioink and a thermal-healing supporting bath were engineered to mimic the mechanical modulus of soft tissue while supporting the formation of self- organizing neurospheroids within elaborate 3D networks. Moreover, bioprinted neurospheroid- laden structures exhibited the capability to differentiate into neuronal cells. These brain-like co- cultures could provide a reproducible platform for modeling neurological diseases, neural regeneration, and drug development and repurposing.