Researchers at Rice University, the University of Washington and others have created a working blood vessel network on a 3D printer that could eventually be part of a human lung or liver. But they stress it is only one step towards building organs that have very complex structures.
By using a water-based gel sensitive to light, they create a chemical reaction. The cells are trapped there and, layer by layer, they build a complex 3D structure. This video explains in more detail how the 3D printed air sac works.
Miller likens the process to the very beginnings of a Lego creation. "It's kind of like the building of the smallest functioning Lego block, characterizing how strong it is, and then using that to build a whole castle."
Stevens verified the technology could also work in a liver but there is still a lot of work to be done considering the liver has 500 functions. "And we tested one of those 500 functions and there is a long way to go," she says. "We will test many more of those functions."
While Stevens and Miller are creating parts of 3D printed organs, Cincinnati Children's Hospital and others are making miniature livers called organoids, using pluripotent stem cells (iPSCs), or cells freshly isolated from human livers.
Miller says organoids are limited in size but he thinks the two methods could be compatible. "We actually see a really big opportunity to load our 3D printed architecture with the differentiating cells that the organoid community is making and it could be a match made in heaven."
He says the two could unify and become highly scaleable. Miller has made his 3D printing files available to the public to let others build on what he's developed. He is commercializing key aspects of the research through a Houston-based startup called Volumetric.