New medical-testing device could improve infectious disease diagnosis thanks to help from the International Space Station
Capillary Flow Experiment work assists researchers in device design.
A new medical-testing device could soon be utilized in the battle against infectious diseases, such as HIV/AIDS and TB, thanks in-part to knowledge gained from a series of experiments conducted aboard the International Space Station on the behavior of liquids. The instrument, which uses the space-tested concept of capillary flow, could be used to improve diagnosis of certain infectious diseases in remote areas.
David Kelso, Clinical Professor of Biomedical Engineering at Northwestern University (IL, USA), had been working to develop a simple and inexpensive device that could be used to test for infectious diseases in resource-limited settings. However, when experimental designs encountered trouble, Kelso recruited the expertise of Portland State University (OR, USA) researcher Mark Weislogel, who is also the principal investigator for the Capillary Flow Experiment on the space station. “He explained to us that the problem had to do with capillary flow,” commented Kelso. “Our mindset was that gravity would pull fluids through the device, but his mindset, due to his work in microgravity, was to use capillary action. His experience and work in zero-gravity was invaluable.”
The device tests cell samples (in the form of blood or other bodily fluids), which, through the action of an enzyme fluid, burst to release DNA or RNA. Another solution then washes away the enzyme and cellular debris, leaving behind the nucleic acid, which is then captured on a bead and used to identify infectious viruses. As Kelso explains, “You only need fewer than a dozen particles, and you can detect the presence of the virus. It’s a phenomenal analytical technique, but it involves four different fluids that have to be moved around.”
This is where capillary forces, the interaction between a solid and liquid that draws a fluid up a narrow tube, become of importance. As these forces continue to act in microgravity, the environment of the space station allowed researchers to conduct experiments into the dynamics of this behavior. The investigations clarified the properties of the boundary between a liquid and the solid surface of its container and the flow of liquids under certain conditions, knowledge that will assist Kelso’s lab in the design of their medical-testing device.
Kelso notes that capillary flow is a way to move fluids without putting any energy into the device. Such a benefit makes it possible to diagnose infectious diseases where power is unreliable, and also reduces time between sample collection and diagnosis, allowing for more timely initiation of treatment. Kara Palamountain, president of the Northwestern Global Health Foundation (IL, USA), adds: “This cartridge and the way fluid moves in it are an important part of measuring viral load level. Capillary flow helped us understand more about our assumptions and explains the movement we see in the cartridge, which we wouldn’t have seen otherwise.” The researchers plan to conduct field studies of the device in Africa by the end of 2014.
Source: NASA press release: Space-tested fluid flow concept advances infectious disease diagnoses.
