Printing Lungs Using 3D, Bioprinting, and Stem Cells
Last month I had the chance to hold a replica of the upper part of a human airway—the windpipe plus the first two bronchi. It had been made from collagen, the biological cement that holds our bodies together. It was slippery and hollow, with the consistency of undercooked pasta.
The structure had emerged from a refrigerator-size 3-D printer in Manchester, New Hampshire, at an outpost of United Therapeutics, a company that earns more than a billion dollars a year selling drugs to treat lung ailments.
One day, the company says, it plans to use a printer like this one to manufacture human lungs in “unlimited quantities” and overcome the severe shortage of donor organs.
Bioprinting tissue isn’t a new idea. 3-D printers can make human skin, even retinas. Yet the method, so far, has been limited to tissues that are very small or very thin and lack blood vessels.
United instead is developing a printer that it believes will be able, within a few years, to manufacture a solid, rubbery outline of a lung in exquisite detail, including all 23 descending branches of the airway, the gas-exchanging alveoli, and a delicate network of capillaries.
A lung made from collagen won’t help anyone: it’s to a real lung what a rubber chicken is to an actual hen. So United is also developing ways to impregnate the matrix with human cells so they’ll attach and burrow into it, bringing it alive.
“We are trying to build the little stick houses for cells to live in,” says Derek Morris, a project leader in United’s organ manufacturing group.