Astronauts to Test How Well Bacteria Can Grow on Different Surfaces in Microgravity
By Irene Ying
An experiment designed by biological sciences students will head to space today to examine how well biofilms can adhere to both smooth and porous aluminum surfaces in microgravity.
An experiment designed by five University of Maryland rising sophomores to test bacteria’s ability to grow on different surfaces in microgravity is scheduled to rocket to the International Space Station (ISS) today.
The experiment, to be carried out by ISS astronauts, is part of the Student Spaceflight Experiments Program (SSEP), which gives students the chance to propose real experiments on the ISS. Terps in Space, UMD’s SSEP community, selected it from numerous proposals as its annual winning experiment to send to the ISS.
The students—Debbie Adam, Michelle Fang, Niki Gooya, Swarnapali “Pali” Keppetipola and Apurva Raghu—are all biological sciences majors and members of the Integrated Life Sciences program in the Honors College.
“I’m extremely proud of our team because the participation of women in science is not as prominent as it should be,” Adam said. “The fact that we have made it this far is really important to me.”
Gooya was the first of the group to enter the space race, years after her eighth-grade team’s SSEP project did not get sent to space. “When I found that Maryland participated in the program, I jumped on it and got my friends to join me.”
The students designed an experiment to study slimy layers of bacteria called biofilms. Biofilms stick to each other and to virtually any surface more strongly than a single bacterium can. They are difficult to get rid of and can lead to human illness. Previous research has also shown that biofilms grow more readily in microgravity, making them an important issue to address on the ISS.
The students’ experiment will examine how well biofilms can adhere to both smooth and porous aluminum surfaces in microgravity. Smooth aluminum is solid, whereas porous aluminum has small holes, or pores, throughout its structure. Previous research has shown that bacteria do not stick well to porous aluminum on Earth.
“A lot of equipment on the ISS is made from aluminum, because it’s economical and easy to work with,” Keppetipola said. “For instance, many tubes used in air filters on the ISS are made of aluminum. If biofilms form in the tubing, bacteria could spread into the ISS’ living spaces and make astronauts sick.”
To design their experiment, the students conducted preliminary research with help from Qiao Ding, a graduate student in the laboratory of Rohan Tikekar, assistant professor of nutrition and food science. The students got support from Birthe Kjellerup, assistant professor of civil and environmental engineering; Timothy Foecke, a scientist at the National Institute of Standards and Technology; and team mentor, Natalia Stepanova, director of Terps in Space.
To test whether bacteria can stick to different aluminum surfaces in microgravity, the students prepared a tube containing dormant E. coli bacteria and two pieces of aluminum—one porous and one smooth. On the ISS, astronauts will add nutrient solution to the bacteria, triggering their activation and growth. After three days, the astronauts will add a preservative to the bacteria-nutrient mixture to kill the bacteria and freeze the cells in place. At the same time, the students will conduct an identical experiment on Earth for comparison.
After the ISS experiment returns to Earth, students will analyze the thickness, area, volume and other physical properties of the biofilms grown on the aluminum surfaces.
If porous aluminum is indeed resistant to biofilm growth in microgravity, the students suggest that other researchers should study how to incorporate more porous materials on the ISS. Ultimately, the students would like to submit their results for publication.
This story was updated to reflect the postponement of the scheduled launch on Sunday, due to bad weather.
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