Left mostly to their own devices, a group of intrepid human stem cells at Vienna’s Austrian Academy of Science knitted themselves into tissue with a variety of brain structures and specialized groups of neurons. In essence, they created a BB-sized neural ball reminiscent of a nine-week-old fetus brain.
And while the clumps of tissue are still a far cry from the complexity of a fully developed human brain, there’s no denying that these neural balls are providing researchers and neuroscientists an unprecedented look at the early stages of human brain development. The work will eventually provide a safe and easy way to test medications directly on human brain tissue, as well as an opportunity to study brain diseases and defects in an entirely new way.
After roughly two months of growth, the original cells developed into the specialized type of neurons that create the distinct parts of a developing brain, including the hippocampus and the choroid plexus. Eventually, the tissue formations also developed parts of the cerebral cortex. And, like an actual brain, the so-called “cerebral organoids” had neurons that were steadily firing electrical messages. Groups of young neurons traveled to different parts of the mini brain; a process that neuroscientists know populates a developing human brain with neurons.
The process of growing these cerebral organoids began with human stem cells taken from embryos and adult skin samples reprogrammed to return to an embryonic-like state. Once developed for a few days in a dish, the cells were later transferred to a specialized liquid designed to encourage neuroectoderm tissue growth. The cells were then injected with a gel substance that serves as a type of scaffold for them to cling to and develop from. The final step was to transfer the gel drops and cells to a spinning flask containing nutrients, which distributed oxygen equally to all of the developing organoid cells.