Being levitated off the ground seems to suit human cells.
Chemist Glauco Souza recently grew a bit of human lung tissue by magnetically levitating it in a pool of liquid full of nutrients and other chemicals that cells need to grow. The method may sound strange, but the tissue Souza and his colleagues created is among the most lifelike ever grown in lab. Their maglev setup could soon grow more true-to-life models of other types of tissues, too. In the far future, similar techniques could be used to grow implantable organs, Souza told TechNewsDaily.
Souza's lung tissue is especially sophisticated: It has four layers of different types of cells, mimicking the layers that appear in the walls of the smallest air passages in working lungs, called bronchioles. As far as Souza is aware, this is the first 3D piece of lung tissue with organized layers of cells that scientists have been able to grow. He and his colleagues, including scientists from Rice University and from a startup he co-founded, are now hoping the tissue can provide a more accurate way of testing the effects of air pollutants, such as ozone or soot, on people. They'll be testing pollutants on their lung tissue.
Scientists constantly need to test the biological effects of drugs, pollutants and other chemicals. The simplest way is to apply the chemicals to lab animals, such as rats, or to human cells grown in flat Petri dishes. Over the past few decades, however, researchers have been developing a third test target: cells grown in more-complex, 3D shapes. The resulting cells react more like live lungs, livers and other tissues than do cells grown in the 2D environment of a flat dish.
In 2010, Souza, then a chemist at the M.D. Anderson Cancer Center in Houston, came up with a unique way of growing cells in 3D. He inserted nano-sized magnets in each of his cells, then levitated the cells inside a liquid broth that fed them. He launched Nano3D Biosciences to develop the technology and has been working to improve it since. In his latest study, he and his colleagues developed a magnetic pen to pull together different layers of tissue that they originally grew separately.
The maglev lung tissue could be especially helpful for research because its creators were able to use a magnet to suspend the lung piece right at the surface of the liquid it is growing in. That's the perfect setup: "The lung cells have air at the top and liquid from the bottom, which is like the lung in the body, where one side is exposed to air and the other side is not," said Shuichi Takayama, a biomedical engineer at the University of Michigan who isn't involved in Souza's work but has developed his own ways of growing tissues in 3D. "This magnetic thing is really nice for the lung cell type."
Souza will find out how nice after conducting pollutant tests on it.
Souza is working on levitating and growing layered pieces of other types of tissues as well, such as heart valves. He's also grown stem cells with his maglev technique, in a step toward regenerative medicine. "That's why people are doing 3D cell culturing," he said.
Implantable organs are a long-term goal, of course. "Complete cellular artificial lungs have a bit of a ways to go," Takayama said. "I think the most advanced one kept a rodent alive for a few hours or something like that."
Souza and his colleagues published their work on their maglev lung Jan. 10 in the journal Tissue Engineering Part C: Methods.