University of Wisconsin Researchers 3D Print Functional Brain Tissue

On Friday, February 1, 2024, researchers at the University of Wisconsin–Madison (UW–Madison) revealed they had developed the first 3D-printed functional human brain tissue. Unlike previous attempts to print functional brain tissue, the researchers altered their printing techniques to create a tool that accurately models neural networks.

“This could be a hugely powerful model to help us understand how brain cells and parts of the brain communicate in humans,” says Su-Chun Zhang, MD, PhD, professor of neuroscience and neurology at UW–Madison’s Waisman Center, in the press release. “It could change the way we look at stem cell biology, neuroscience, and the pathogenesis of many neurological and psychiatric disorders.”

According to the UW-Madison press release, traditional 3D bioprinting involves stacking layers of biopolymers vertically; however, the researchers opted for horizontal printing. The study published in Cell Stem Cell noted that horizontal printing allowed them to develop neural tissues that form functional connections. Additionally, horizontal printing made it easy for researchers to conduct live-cell imaging and electrophysiological recordings while overcoming the thickness challenges of horizontal printing.

Additionally — veering away from traditional 3D bioprinting yet again — the researchers used neurons produced from pluripotent stem cells in a softer bio-ink gel. Previously, firmer gels have been used to maintain structural integrity. However, researchers note that the new gel is still strong enough to hold the structure while being soft enough to allow the neurons to grow and connect with each other.

In the press release, the study leaders noted that the unique printing approach allows them to develop thin layers of tissue that allow neurons to get the appropriate levels of oxygen or nutrients using precise technology.

Uniquely, the researchers reported that the neuronal tissue printed using this method yields neurons that can communicate, send signals, and interact with each other using neurotransmitters.

“In the past, we have often looked at one thing at a time, which means we often miss some critical components. Our brain operates in networks. We want to print brain tissue this way because cells do not operate by themselves. They talk to each other. This is how our brain works, and it has to be studied all together like this to truly understand it,” Zhang says. “Our brain tissue could be used to study almost every major aspect of what many people at the Waisman Center are working on. It can be used to look at the molecular mechanisms underlying brain development, human development, developmental disabilities, neurodegenerative disorders, and more.”

Although more studies are needed to validate the tissues and their applications in clinical research, the implications of this research are vast, including studying neurodevelopmental and neurodegenerative disorders.