Research funded by the U.S. National Science Foundation (NSF) and sponsored by the International Space Station (ISS) National Laboratory could lead to advancements in biomedicine, including enhanced detection of viruses and improved drug therapies for diseases.
Projects from researchers at Lehigh University and the University of California, Santa Barbara, will leverage microgravity conditions to advance fundamental understanding of the movement of particles and liquids through other liquids and gels. Improving knowledge of the physical forces affecting this motion may lead to better medical technologies for detecting and treating human disease. The investigations were awarded through a joint solicitation from NSF and the Center for the Advancement of Science in Space, Inc. (CASIS), manager of the ISS National Lab, for research in the field of transport phenomena.
Optimizing Devices for Virus Detection
The project from Lehigh University could someday enable the next generation of portable microfluidic devices that use bioseparation for virus detection. Bioseparation relies on thermophoresis—the tendency of particles suspended in a solution to move from hot to cold regions along a temperature gradient—to separate particles from bodily fluids. The physical separation of viral particles from the fluids allows researchers to detect the presence and load of viruses in laboratory samples.
Through their ISS National Lab-sponsored investigation, James Gilchrist, professor in the Lehigh College of Engineering and Applied Science, and his team aim to tease apart the physical forces driving thermophoresis in a range of complex fluids. Previous ground-based experiments have been confounded by the presence of gravity-induced convection. Convection creates currents in the fluid due to the circulation of particles and liquids of differing densities. On Earth, these currents can interfere with efforts to measure motion caused by thermophoresis.
By removing the effects of convection in microgravity, Gilchrist and his team could obtain the best data yet on the mechanisms behind thermophoresis, clearing the path to explore its utility for bioseparation. If successful, the results will be used to analyze the function of current bioseparation devices and improve their efficiency.
“We could potentially design particles of different chemistry or different shapes or sizes that would move more efficiently by thermophoresis, or we could design a complex fluid to enhance that process,” Gilchrist said. “Our goal in this experiment is to take some fundamental measurements that we can apply in a theoretical way but also in an empirical way of optimizing these systems to enhance separations and the detection of viruses.”
Improving Treatments for Respiratory Illness
The project from the University of California, Santa Barbara aims to understand how naturally occurring complex fluids in the body impact a specialized drug delivery method used to treat respiratory illnesses. Emilie Dressaire, assistant professor in the University of California, Santa Barbara College of Engineering, will leverage microgravity conditions to better understand how the mucus lining of the airway system affects the motion of “plugs” of liquid through the airway. Liquid plugs are used to deliver therapeutic drugs from the airway to the lungs in surfactant replacement therapy, a common treatment for respiratory distress in infants and adults. Dressaire’s research seeks to understand the dynamics of fluids as they move through gel-coated tubes, which mimic the mucosal lining in the human lung. This research could contribute to a more realistic model of plug flow that could lead to improved drug delivery, resulting in a higher treatment success rate.
“Surfactant replacement therapy has had a lot of success in premature babies. It’s really extending that therapy to adults that has not been quite as successful, and we’d like to understand why,” Dressaire said. “Our hope is that if we better understand how the mucus is affecting the transport of the plugs, then we can modify how to approach treatment and get the most out of it.”
By performing the experiment in microgravity, Dressaire’s team can limit the effects of gravity—which, along with surface tension, helps to drive the motion of liquid plugs through the airways of patients on Earth. At smaller scales (for example, in the tiny air passages deep in the lungs) the effects of surface tension are conflated with the effects of gravity, making it difficult to discern the actions of the individual forces. Reducing the action of gravity will allow Dressaire’s team to observe the isolated effects of surface tension on liquid plug motion through the gel substrate—an opportunity that would not be feasible in a laboratory on Earth.
“I don’t think there is a scientist who hasn’t dreamed of working with the ISS and NASA and getting their experiment to space—it just lets you do things you can’t do anywhere on Earth,” Dressaire said. “For us, this was a bit of a dream come true, and we’re incredibly excited.”