Elain Fu says her passion for research is fueled by a desire to create devices that can have a real impact on global health care delivery.
“I’m very motivated by applications,” said Fu, assistant professor of bioengineering in the College of Engineering at Oregon State University. “I love to do quantitative science, and to design devices. But the main satisfaction I get from my work is that it’s driven by biomedically relevant problems.”
With a background in physics and bioengineering and expertise in building microfluidic sensors, Fu’s current research focus is on creating inexpensive, paper-based tools for diagnosing and monitoring a variety of different health conditions. Such devices are a natural fit for what are known as “low-resource environments” – rural communities in the developing world, battlefields, and other remote locations where medical facilities and personnel aren’t always available. But the devices have the potential for a variety of applications in a wide range of environments.
“The area where I have the most experience is human disease diagnosis,” Fu said. “But there are a lot of different application domains – such as veterinary medicine, environmental monitoring, and military situations – where you might need a sensor that you can use in a setting that doesn’t have trained operators, laboratory facilities, or even electricity. By building the capability of these devices within a more general platform, the hope is that the devices will be useful for many different applications.”
One popular format for a paper-based microfluidic device is the lateral-flow test, its best-known implementation being the home pregnancy test that has been in use for decades. This type of device uses capillary action to move a liquid sample through a strip of porous medium, where it can react with certain chemicals, fixed into designated zones along the strip, to display a visible result.
“The format has many strengths for low-resource settings, so it is used around the world for diagnosing infectious diseases, such as malaria and dengue fever,” Fu said. “The problem is that this type of test is not always sensitive enough or precise enough for a given application. So a lot of work is being done in the paper microfluidics community to take the best aspects of the lateral-flow test and make even better tests.”
What constitutes a “better” test varies, depending on the application. For example, in diagnosing malaria, a better test translates to a test with a lower limit of detection. So engineers can manipulate the fluids on the device, or the signaling molecules within them, to create a higher signal-to-noise ratio and improve performance.
Fu’s previous projects have included tests to detect influenza and malaria. One of her current projects, in collaboration with colleagues at the University of Washington, aims to develop an early-detection HIV diagnostic for infants. Testing for HIV in newborns presents special challenges, Fu says, because maternal antibodies inherited in the womb can create interference.
“Those maternal antibodies are good for the infant whose immune system is still developing,” Fu said. “But they can create false positives. The test we’re developing has to have an extra component on the front end to pull out the maternal antibodies, so we have to do a little more work. We’re also pushing for higher sensitivity, because with a lower detection limit, you can hopefully diagnose and begin treatment earlier.”
Another application where paper-based microfluidics shows great promise is in-home monitoring of chronic health conditions. One example is phenylketonuria, or PKU, a genetic disorder in which the body is not able to properly metabolize the amino acid phenylalanine.
“The idea is that people with PKU need to monitor their phenylalanine levels just like people with diabetes need to monitor their glucose levels,” Fu said. “But in the absence of any sort of easy test, they have to go to a clinic to get their blood drawn. Then maybe a week or two later, they get the results. That’s informative on some level, but it doesn’t provide the real-time feedback patients need to effectively change their therapy.”
So, a few years back, Fu embarked on a project to develop a test for phenylalanine monitoring in the home. With support from the National PKU Alliance, she and her students created a working prototype that performed well under lab conditions. But it’s a much higher bar to build something that can perform robustly in somebody’s home, with the patient operating it. Last September, the National Institutes of Health awarded funding to Fu and collaborators at the University of Pittsburgh and Oasis Diagnostics to try to move that device to the next level.
“What we’re trying to do is create a device for people with PKU, so they can take a drop of blood from a finger prick, put it in the device, and then within 10 minutes get their phenylalanine level.” Fu said. “This is where it gets exciting for me, moving from something where you can demonstrate that it works in the lab, to something that people can actually use in their own home.”
The drive to create a home-based phenylalanine test is just one example of a growing trend toward more personalized health care. Fu says this trend has the potential to empower individuals with a variety of different conditions, by providing them with tools for home-based testing and monitoring.
“Technology is moving out of centralized labs and hospitals and becoming more accessible to people for use at the point of care,” Fu said. “This trend can enable the practice of precision health in which differences between individuals can be taken into account in their healthcare. Having one number that you’ve averaged over the population to say what’s normal or not normal – that’s not really meaningful. But if patients could simply test themselves at appropriate times at home or wherever they happen to be, they would be able to map out exactly what is and is not normal for them.”
Fu says she’d ultimately like to see her devices progress far enough to where she can transfer her technology to an industry partner to produce the technology for use by the people who need it.
“What’s meaningful to me, and what drives my research, is the potential for helping people,” she said.