In vitro bioengineered model of cortical brain tissue

Developers

Karolina Chwalek, Min D. Tang-Schomer, Fiorenzo G. Omenetto, David L. Kaplan.

Description of the technology

A bioengineered model of 3D brain-like tissue, being a core of this technology, was developed using silk-collagen protein scaffolds seeded with primary cortical neurons. The scaffold design provides compartmentalized control for spatial separation of neuronal cell bodies and neural projections, which resembles the layered structure of the brain (cerebral cortex). Neurons seeded in a donut-shaped porous silk sponge grow robust neuronal projections within a collagen-filled central region, generating 3D neural networks with structural and functional connectivity. The silk scaffold preserves the mechanical stability of the engineered tissues, allowing for ease of handling, long-term culture in vitro and anchoring of the central collagen gel to avoid shrinkage, and enabling neural network maturation. This protocol describes the preparation and manipulation of silk-collagen constructs, including the isolation and seeding of primary rat cortical neurons. The protocol of construct assembly takes 2 d, and the resulting tissues can be maintained in culture for several weeks.

Practical application

This 3D technique is useful for mechanical injury studies and as a drug screening tool, and it could serve as a foundation for brain-related disease models. Particularly, the technology shows that the 3D brain tissue model can be applied to the study of traumatic brain injury. The tissue model responds in vitro with biochemical and electrophysiological outcomes that mimic observations reported in vivo. Moreover, the tissue model allowes for real-time nondestructive assessments such as local field potential measurement and liquid chromatography on culture medium supernatants. Besides, it can offer new directions for studies on brain homeostasis and injury.

The cellular complexity of the model can be further increased by the inclusion of other brain-derived cell types such as astrocytes, microglia and oligodendrocytes, in order to study cell-cell interactions and their effects on brain structure and function during homeostasis and regeneration and repair scenarios.
The protocol can also be adapted to develop new disease tissue models for disorders such as Alzheimer’s disease, Parkinson’s disease or epilepsy, by using human patient-derived induced pluripotent stem cells.

Laboratories

• Department of Biomedical Engineering, Tufts University, Medford (USA)
• Connecticut Children’s Medical Center, Departments of Pediatrics, Farmington (USA)
• Department of Physics, Tufts University, Medford (USA)

Links

Publications

• Chwalek, K. et al. «In vitro bioengineered model of cortical brain tissue." 10 Nature Protocols (2015): 1362–1373.
• Hopkins, A.M. et al. «3D in vitro modeling of the central nervous system." 125 °C Prog. Neurobiol. (2015): 1–25.
• Vepari, C. & Kaplan, D.L. «Silk as a biomaterial." 32 Prog. Polym. Sci. (2007): 991–1007.