We’re printing brains and hearts now

3D-printing brain tissue

This story comes to us from the University of Wisconsin-Madison, where researchers developed a new bioprinting method specifically for brain tissue.

You can imagine why brain tissue is special: The human brain is an organ with more mysteries than most. The malleable connectivity of the brain makes it a particular challenge to recreate. That’s why scientists aren’t trying to create a whole human brain here—they’re starting with some brain tissue.

The new technique relies on a horizontal 3D-printing approach—rather than the traditional layer-upon-layer method of traditional 3D-printing. With this approach, the researchers placed neurons grown from induced pluripotent stem cells in a soft bioink gel. 

The result?

A printing method with greater control over cell type and arrangement than traditional brain organoids used in research and drug development.

“Our tissue stays relatively thin and this makes it easy for the neurons to get enough oxygen and enough nutrients from the growth media,” said researcher Yuanwei Yan.

The 3D-printing brain tissue functions much like a regular brain, in that it can form networks and communicate through neurotransmitters.

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

What is a heart on a chip?

This next story also features bioink innovation, but this time from Centre de recherche Azrieli du CHU Sainte-Justine, a think tank affiliated with the Université de Montreal. 

These researchers’ bioink is intended for personalized “heart on a chip” devices. Which, similarly to the UW-Madison project, is a bit like an organoid, but not.

The bioink’s composition—which includes a variety of natural polymers, cell types, and electroconductive nanomaterials—permits the creation of a tiny device which most closely resembles the function of a human heart. 

“We’ve formulated a bioink that best reproduces the properties of the heart, such as elasticity and electrical conductivity, and has suitable properties required for 3D bioprinting,” said first author Ali Mousavi.

The resulting heart on a chip device is ring shaped and can fit on the tip of a finger. And the researchers plan to make many more of them. In the future, they hope to use cells from cardiac patients, making the devices personalized for specific heart disease cases.

“Our research has made it possible to combine 3D bioprinting technology to produce standard hearts-on-a-chip much more quickly and precisely,” said pharmacology professor Houman Savoji. “What’s more, our results show that printed devices perform better than those produced manually.” 

Our perspective: A boon for researchers—and eventually, for patients

When we discuss 3D-printing human body parts, it can be easy to let our imaginations run wild.

After all, the last time we touched on this topic, we were bringing you the story of astronauts potentially receiving 3D-printed knee components in space. 

These innovations—which are closer to organoids than true human hearts and brains—will primarily serve researchers. At least at first.

The UW-Madison team has emphasized how re-creatable their process is for other labs. The Montreal team’s innovation intends to move cardiac research in a more personalized direction. Eventually, through the development of more personalized therapies with these next-generation organoids, patients will benefit.

When we consider the possibilities and implications of new technology, it can be easy to be swept up in science fiction assumptions—and then feel deflated that we’re not quite at full-organ 3D-printing levels yet. But we must continue celebrating all the steps of innovation along the way, while championing science literacy about what is and isn’t possible yet.

And who knows? Further amazing 3D-printing innovations may be here sooner than we think.