Scientists create first ‘functional’ 3D printed brain organoids

Scientists at the University of Wisconsin-Madison (UWM) announced they have created the first 3D-printed brain organoids that function like natural brain tissue.

“Neurons communicate, send signals, interact through neurotransmitters, and even form appropriate networks with supporting cells added to the printed tissue,” said lead author Su-Chun Zhang. said.

Challenge: Under the right conditions, stem cells self-assemble into small three-dimensional tissues that mimic features of the human brain. These “brain organoids” can be used for things like drug testing and disease research.

Because brain organoids self-assemble, researchers have less control over the final structure, and the mini-brains may not grow into the best design for their research.

“They were still able to speak to each other in a very special and specific way.”

Zhang Su-chun

Some scientists are trying to use 3D bioprinting to gain greater control over the location and types of brain cells within organoids, but they are still trying to use 3D bioprinting to get soft “ink” filled with these cells into place. They are difficult to maintain, and using stiffer materials or scaffolds prevents cells from naturally bonding to each other.

3D printed brain organoids: The UWM team took a different approach to their research, which was published in the journal Cell Stem Cell.

First, they induced stem cells to begin developing into different types of brain cells. These various cells were mixed with a hydrogel to create a printable “bioink.”

Instead of stacking layers vertically, which is traditional 3D printing methods, the UWM team went horizontal and placed strips of bioink next to each other. This meant that the 3D-printed brain organoids were only 50 micrometers “tall,” but their thinness ensured that the neurons got the oxygen they needed.

As expected, this approach also led to the formation of natural connections between cells in the minibrain. Different types of cells in different layers were able to send signals to each other, forming networks similar to those found in natural brain tissue.

“This tissue still has enough structure to hold it together, but is soft enough that neurons can grow into each other and start talking to each other…When we print different cells that belong to different parts of the brain, But they were still able to ‘talk to each other in very special and specific ways,’ Chan said.

Future prospects: The researchers will continue to improve their technology and look for ways to further control the orientation of cells in their 3D-printed brain organoids, perhaps by making changes to the bioink.

They hope that other labs may adopt the technique for their own research, given that it does not require special equipment. They used commercially available bioprinters and standard imaging techniques for their research.

“This could be a very powerful model to help us understand how human brain cells and parts of the brain communicate,” Zhang says. “It has the potential to change the way we look at stem cell biology, neuroscience, and the pathogenesis of many neurological and psychiatric diseases.”

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