Stop by Khalid Salaita's office in the Atwood chemistry building and you may find a tag hanging on the door handle with an image of the International Space Station (ISS). "I'm busy working on my ISS National Lab project," the placard reads.
Go ahead and knock. Salaita will gladly tell you about his lab's latest mission.
"We're going to space!" says Salaita, Samuel Candler Dobbs Professor of Chemistry. "Or, more accurately, we are sending our force probes to the ISS to study how cell mechanics change at microgravity."
Salaita took this selfie to show some of the International Space Station "swag" his lab has received as part of the project.
Salaita is a pioneer in the field of molecular mechanobiology. His lab developed probes, or sensors, made of synthetic DNA to measure the miniscule forces involved in the functioning of cells. The technology can detect mechanical forces as fleeting as the blink of an eye and as faint as piconewtons — about one billionth the weight of a paperclip.These tools have opened the door to studying the mechanics of everything from immune system activation to the formation of stem cells and the clotting of blood.
A grant from the National Science Foundation (NSF) and the Center for the Advancement of Science in Space is funding Salaita's three-year project for studying mechanobiology in the microgravity atmosphere of low-orbit Earth. During the next year, his lab will prepare its force probes for space travel and for experimentation aboard the ISS National Laboratory.
"I've always talked to my kids about what I do but this is the only time they've gotten excited about it," Salaita says. "Finally! They're a tough crowd."
The whole family plans to travel to the launch site about a year from now when the force probes will be loaded onto a rocket to blast off for the ISS.
In the following Q&A, Salaita explains some of the challenges involved in doing scientific experiments in space and how the project may benefit humanity.
What got you interested in this project?
Human biology drastically changes at microgravity. The bone density of astronauts decreases rapidly during space flight. Their immune systems and the way their blood clots become dysregulated. The patterns of their protein-expression and gene-expression drastically change.
Aging is accelerated. Each day that an astronaut spends on the International Space Station is like 10 days on Earth. Isn't that wacky?
Previous experiments with cells in petri dishes on the space station show that the architecture of cells change. Individual cells look and behave very differently at microgravity. That means that cells are somehow feeling and responding to gravity even though cells are so tiny and the forces involved are so miniscule.
I find that fascinating. Why and how does this happen?
How did you get the funding?
I saw a call for grant proposals on the NSF website to study tissue engineering and mechanobiology on the space station and my lab immediately applied. I thought that was the coolest thing that we could possibly do with our cellular-force probes.
Our first proposal was rejected. The experiment we came up with involved drawing blood from the astronauts while they were on the space station. There were some obvious logistical challenges with that idea. And we realized that astronauts do not like being used as guinea pigs.
We decided to try again. I contacted an Emory colleague, Chunhui Xu, [professor of pediatrics in the School of Medicine], who had received funding for a project to study how heart cells perform on the International Space Station.
She was very generous with her time and knowledge. We followed her advice, designed experiments to be conducted on cells in a petri dish, and our reworked proposal was accepted.
We developed a hypothesis: cells respond to changes in gravitational fields by altering the way they anchor themselves in place. Just like a tent needs stakes to anchor it to the ground, a cell builds adhesions as anchor points to a living tissue or to a glass petri dish.
Chemistry graduate student Maia Vierengel and research scientist Hiroaki Ogasawara are the members of my lab heading up the project.
What are some of the challenges of doing science in space?
One big challenge we're working on now is how to prepare our synthetic DNA force sensors so that they will survive the trip to space. They need to be frozen and stored in the cargo bay of the rocket. We're restricted on the materials we use to pack them because every gram of weight adds about $100 to the shipping cost.
We will also need to prepare and freeze our samples of immortalized cells. These are common fibroblast cells that have been modified so that they will grow indefinitely in a petri dish.
The force probes and the cell samples will be thawed so they come alive again once they reach the space station.
We need to minimize the number of steps needed to run the experiments. And we have to build special hardware to conduct them. Things don't just sit in a normal petri dish at microgravity.
After allowing the cells to grow and then applying the force probes, the astronauts will need to stop the process with a fixative, paraformaldehyde. Finally, the samples will have to be frozen again and prepared for shipment back to Earth so our lab can analyze the results.
What do you hope to learn?
Understanding how cell functions are altered at microgravity will help us better understand their mechanobiology on Earth. We hope to apply what we learn to further refine our force probes and to continue expanding their use in biomedical sciences.
Our force probes are already being using by research groups around the world studying the mechanobiology of everything from immune cells to neurons and even different types of cancer cells. Here at Emory, we're conducting human trials using the force-probe technology to better predict the risk of bleeding dysfunction in cardiac patients.
