A new type of bioink has been used to 3D print lung tissue and tested in mice. In a study published in Advanced Materials, scientists describe how they bioprinted airways structures with a lung tissue specific bioink and transplanted it into a mouse.
Being able to 3D print human organs could help millions of people each year who are in need of a transplant. This research team focused specifically on the lungs. While the researchers haven’t printed an entire set of lungs, they demonstrated that they can print segments that could be transplanted.
“We started small by fabricating small tubes, because this is a feature found in both airways and in the vasculature of the lung. By using our new bioink with stem cells isolated from patient airways, we were able to bioprint small airways which had multiple layers of cells and remained open over time,” explains Darcy Wagner, who is an associate professor at Lund University and is the senior author of the study, in a press release.
Printing living tissue works similarly to printing other physical objects in three dimensional space. There needs to be a machine that can lay the ink down in layers, building up the object layer by layer. The only difference with 3D printing organs is that the ink involves living cells and a bioengineered scaffolding.
The bioink includes material derived from seaweed, alginate and extracellular matrix from lung tissue. It also included stem cells found in lungs that are able to produce many of the cells needed in the organ. Because they used stem cells that can differentiate into various types of cells, this makes the bioink versatile.
“These next generation bioinks also support the maturation of the airway stem cells into multiple cell types found in adult human airways, which means that less cell types need to be printed, simplifying the nozzle numbers needed to print tissue made of multiple cell types,” says Wagner in the press release.
The 3D-printed airways in this study are small, about 4 to 6 mm in diameter. The small airways were transplanted into a mouse, were tolerated by the mouse’s body and supported new blood vessels.
“We hope that further technological improvements of available 3D printers and further bioink advances will allow for bioprinting at a higher resolution in order to engineer larger tissues which could be used for transplantation in the future. We still have a long way to go,” says Wagner in the press release.
The team hopes that this success with the new bioink will mean that they’ll be able to test it out on larger animals in the future. It might be still quite some time before humans can order a 3D printed organ when needed, but we’re that much closer with each new study.
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