Researchers studying how bubbles form and function have sent a fully automated, self-contained experiment to the International Space Station (ISS) aboard a Space X rocket that launched this afternoon.
The study, led by Tengfei Luo, a professor in the Department of Aeronautics and Mechanical Engineering at the University of Notre Dame, will be initiated by astronauts on the International Space Station. Using real-time results sent back to Earth for analysis, Lu and his team hope to gain a better basic understanding of how bubbles form, grow and separate from solid surfaces with different nanoscale features.
This information can improve the diagnostic ability of life-threatening diseases, including some types of cancer.
“What we’re looking for in parallel with research being done on the International Space Station is how to use these bubbles to detect early-stage cancers — when cancer cells are still in very low concentrations,” Lu said. “Our method is a potential way to increase sensitivity and improve early detection of cancer.”
In a 2020 study published in Advanced Material InterfaceLuo successfully used laser heating to generate bubbles in a solution containing biological molecules. The researchers found that they could attract these biomolecules to bubbles and deposit them on the surface, creating “highly concentrated islands”. The findings could influence future development of highly sensitive diagnostics – a topic of study Luo is working on with funding from the National Science Foundation.
Several competing factors can affect bubble dynamics: gravity, which affects the buoyancy of the bubble; Bubble interface and solid surface, or capillary force; The surface tension is reduced as the bubbles try to become balls in the liquid. Lu’s experiments on the International Space Station will test how bubbles behave in the absence of gravity.
“One of the questions we want to answer is, without the buoyancy effect, how would the other two factors affect bubble dynamics?” Luo said.
Bubble behavior is key when used to collect biomarkers for early cancer detection.
We want the bubbles to stay on the surface as long as possible so they can collect more biomolecules in solution. If it’s too big, it will separate, so we wanted to know how to engineer the surface – using nanostructures on the surface to increase capillary forces and keep bubbles on the surface for a longer period of time. We know that buoyancy is a big factor and can prevent a bubble from growing too large before it bursts, which is why we thought of looking at an environment where there is no gravity to allow us to clarify the basic physics.”
Tengfei Luo, Professor in the Department of Aeronautics and Mechanical Engineering at the University of Notre Dame
Luo received funding from the Center for the Advancement of Science in Space and began work on the International Space Station project in 2018, but has faced a number of delays, including delays due to the COVID-19 pandemic.
For the experiment, he needed a device that could create bubbles and record visuals and readings of bubble behavior without the use of a laser—which would cost an additional $2 million—and without biomolecules, which, in space, could pose biological problems. . “So we focused on the basics,” said Lu.
Working with Space Tango, a company that specializes in designing and building medical devices and robotic technology for use in space, the Notre Dame probe will be installed on the International Space Station in June.
The probes are housed in a small cube, known as the CubeLab, which is equipped with four fluid compartments, the thermal capability to heat the solution, and a camera that captures and sends images to each compartment in the near future. Lu and his team will also receive temperature and pressure readings as well as heating energy values.
“We will compare these results with what we already know about bubble dynamics on Earth, giving us a better understanding of the role the different fluid forces play,” Lu said.
The experiment will last for about three weeks on the International Space Station.
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