Research Stories

by Margaret Coulombe

There is plenty of competition among researchers to get an experiment flown into orbit on board the Space Shuttle or the International Space Station. Room on these crafts is expensive—$10,000 per poud of equipment. Not to mention the miles of NASA red tape that must be waded through. Prior to winning that scientific lottery several times, ASU microbiologist Cheryl Nickerson and her NASA colleague Mark Ott did lots of ground-based studies in the laboratory.

They used a self-contained cell growth chamber designed by NASA. The tool is called a rotating wall vessel (RWV) bioreactor. The device is a hollow cylinder that is completely filled with culture media and cells. When the bioreactor rotates, the cells can't settle. They are kept in freefall. The environment for the cell culture simulates the low fluid shear aspects of spaceflight.

"You can think of fluid shear as the motion of fluid over the surface of cells," Nickerson explains. "The low fluid shear environment encountered by cells during growth in the bioreactor is also relevant to conditions that they encounter on Earth during their natural lifecycles—especially for pathogens inside the human body."

Understanding the mechanical forces operative in the culture environment is important. Scientists want to know how cells respond to these forces at a molecular level. That information can have applications to human health in other ways, such as in tissue engineering.

The RWV bioreactor also is used to grow human cells and tissues in the laboratory that closely mimic functional tissues in the body. Nickerson's team has used the bioreactor to develop advanced three-dimensional tissue models called organotypic models. They have applied these models to study infection by a variety of different human pathogens. The researchers have found that these models respond to infection in ways that model important aspects of the infection process in animals and humans.

The RWV is the best-accepted model for growing cells in the lab under conditions that simulate spaceflight, Nickerson says. It is a powerful tool. Scientists use the RWV to understand both the effects of microgravity in space and physiological conditions that infectious agents face in the body on Earth.

"The use of bioengineered model tissue systems may lead to the development of new ways to diagnose, treat and prevent illness. That is so cool!" Nickerson adds.

Read more about Cheryl Nickerson and her research in "Space ills and Earth cures."