Composite Material Replicates Brain Tissue's Grey and White Matter to Study Neurons in 3D

The neurons formed functional networks throughout the scaffold pores (dark areas). Image courtesy of Tufts University.

Diagram of scaffold donut showing grey-white matter compartmentalization. Rat neurons attached to the scaffold (donut ring) and also sent axons (labeled with green fluorescence) through the collagen gel-filled center.

Neurons of the brain are notoriously difficult to study in a laboratory environment because neurons grow and connect to other neurons in a complex 3D environment. Scientists at the Tissue Engineering Resource Center at Tufts University have developed a new material that in many ways replicates how the brain functions, allowing them to study neurons up close for extended periods of time.

Previously, gels were used to provide a hospitable environment for neurons, but survival and growth of new cells within them has been very limited. This is because a gel simply does not have the complexity that resembles brain tissue, including disparate regions of grey and white matter which contains neurons and axons, respectively. The newly created tissue-like material has separate regions of grey and white matter and was seeded with rat primary cortical neurons. In the laboratory, the cells lived for more that two months, considerably longer than was possible before in a 3D environment. The material consists of a scaffold made of silk protein and a collagen-based gel, the two wafers placed into a doughnut-like shape of concentric circles.

The researchers are hoping that among other uses of this engineered tissue will be studying how brain damage affects neurons, axons, and the intersection between grey and white matter. To that end they already have some findings to report, according to the study abstract in Proceedings of the National Academy of Sciences:

We show that, on injury, this brain-like tissue responds in vitro with biochemical and electrophysiological outcomes that mimic observations in vivo. This modular 3D brain-like tissue is capable of real-time nondestructive assessments, offering previously unidentified directions for studies of brain homeostasis and injury.

Study in PNAS: Bioengineered functional brain-like cortical tissue…

NIH: Bioengineers Create Functional 3D Brain-like Tissue…