Researchers have used stem cells to develop functional 3D models of human brain tissues.
Amazingly, growing mini-brains in laboratories to study how the human brain works is no new feat. However, a team of researchers from Tufts University in Massachusetts has adopted a new approach to building a more accurate 3D model of human brain tissues.
Instead of using brain tissues, which are usually only available for removal post-mortem from volunteers, Tufts University neuroscientists populated their 3D models with human induced pluripotent stem cells (iPSCs) which can be readily taken from many sources.
“We found the right conditions to get the iPSCs to differentiate into a number of different neural subtypes, as well as astrocytes that support the growing neural networks,” David Kaplan, chair of the Department of Biomedical Engineering at Tufts’ School of Engineering, said.
The 3D models produced by Kaplan and his team have a more complex mix of cells exhibited by neural tissues as compared to the lab-grown and cultured 2D models. However, this is only attainable with the right morphology and expression of receptors and neurotransmitters, the researchers said.
The team’s method is a mix of the conventional approaches that make use of tissue-like hydrogels and porous polystyrene scaffolds. They create a web-like matrix from fibroin, a kind of silk protein, to space out the cells. They then immersed the fibroin in a collagen hydrogel to support the structure.
“The silk-collagen scaffolds provide the right environment to produce cells with the genetic signatures and electrical signaling found in native neuronal tissues,” Kaplan added.
The balanced structure ensures that the stem cells are evenly spaced out. It also became an ideal place for the stem cells to settle and grow into the healthy variety of cells found in adult human brains.
“The growth of neural networks is sustained and very consistent in the 3D tissue models, whether we use cells from healthy individuals or cells from patients with Alzheimer’s or Parkinson’s disease,” William Cantley, one of the researchers, went on to say. “That gives us a reliable platform to study different disease conditions and the ability to observe what happens to the cells over the long term.”
The researchers plan to study the 3D models of human brain tissues using advanced imaging techniques. They are also looking into the possibility of adding more cell types into the 3D models like microglia and endothelial cells.