Researchers are exploring the potential of the International Space Station’s microgravity environment to improve the sensitivity of biosensors used for cancer detection, leading them to investigate a compelling possibility: Could the key to earlier cancer detection lie in the behavior of bubbles in space? Studies on the ISS are showing that it just might, as the absence of gravity can be harnessed to concentrate microscopic substances like cancer biomarkers, potentially leading to more sensitive diagnostic tools.

Featured in Upward, the official magazine of the ISS National Laboratory, the research focuses on manipulating bubbles in microgravity to efficiently collect and concentrate microscopic particles from liquid samples such as blood.

Leading the research team focused on the project was Professor Tengfei Luo, director of the Molecular/Nano-Scale Transport & Energy Research Laboratory (MONSTER Lab) at the University of Notre Dame.

“The technology currently available to screen for early, asymptomatic cancer before a tumor is visible during imaging is very limited to just a few cancers,” said Luo, in the Upward article. “If cancer screening using our bubble technology in space is democratized and made inexpensive, many more cancers can be screened, and everyone can benefit. It’s something we may be able to integrate into annual exams. It sounds far-fetched, but it’s achievable.”

The microgravity-enhanced bubble technology also shows promise for environmental applications, as Luo’s team has successfully used it to detect low concentrations of microplastics, including nanoplastics between 1 and 1,000 nanometers in size, in ocean water samples.

Microgravity’s impact on bubble behavior

Under Earth’s gravity, buoyancy makes bubbles rise in boiling water, while thermal convection creates fluid currents that detach them from surfaces. These forces restrict bubble growth and stability. Yet in microgravity, buoyancy and convection are minimal. These conditions allow bubbles to grow larger and remain attached to surfaces for extended periods. Consequently, the prolonged contact between the bubble and the surrounding liquid, combined with surface tension gradients known as the Marangoni effect, generates unique fluid dynamics that researchers can harness to concentrate particles.

Inside an automated lab

To study bubble behavior in microgravity, the research team, in partnership with Space Tango, developed a compact, automated laboratory called CubeLab. This mini-lab, equipped with fluid chambers and high-speed cameras, was sent to the International Space Station (ISS).

Inside CubeLab, researchers used lasers to precisely heat nanoparticles within liquid samples, creating bubbles at specific locations. The high-speed cameras captured the bubbles’ growth and interaction with the surrounding particles in the absence of Earth’s gravity. This precise bubble generation allows for controlled studies of bubble dynamics and their interaction with particles

The ISS experiments showed that bubbles in microgravity grow significantly larger and remain stable for much longer than bubbles on Earth. This enhanced stability, coupled with a phenomenon called the Marangoni effect, allows the bubbles to effectively concentrate nanoparticles from the surrounding liquid. This finding could have implications for the development of more sensitive biosensors, as a higher concentration of target molecules, such as cancer biomarkers, could pave the way for earlier and more accurate disease detection.