New device could deliver bedside blood test results in an hour

University of Colorado Boulder researchers hope to change that with a new handheld, sound-based diagnostic system able to deliver precise results in an hour with a mere finger prick of blood.

The team describes the system in a new paper published Oct. 16 in the journal "Science Advances."

"We've developed a technology that is very user-friendly, can be deployed in various settings and provide valuable diagnostic information in a short time frame," said senior author Wyatt Shields, assistant professor in the Department of Chemical and Biological Engineering at University of Colorado Boulder.

The findings come as scientists have been racing to democratize diagnostic testing, which can be hard for people in rural areas or developing countries to access and, in the case of blood tests, frightening for those averse to needles.

While existing rapid tests like COVID tests or pregnancy tests can provide a quick "yes" or "no" as to whether a specific biomarker in the blood or urine is present, they typically can't say how much, and they aren't sensitive enough to detect very small amounts.

Meanwhile, the gold standard for clinical blood tests is highly sensitive and can detect rare or scarce biomarkers, but it requires expensive equipment and complex techniques and can take days for patients to receive results.

The authors acknowledge that skepticism exists in the biosensing field since the downfall of blood-testing company Theranos Inc., which promised in 2015 to detect hundreds of biomarkers with a drop of blood. Their invention works differently, they said, and unlike the now-defunct start-up, it is based on systematic experiments and peer-reviewed research.

"While what they claimed to do isn't possible right now, a lot of researchers are hoping something similar will be possible one day," said lead author Cooper Thome, a PhD candidate in the department. "This work could be a step toward that goal -- but one that is backed by science that anybody can access."

Sound diagnostics

Shields and Thome set out to develop a tool that is simultaneously sensitive, highly portable and easy-to-use.

Their secret ingredients: Tiny particles they call "functional negative acoustic contrast" particles (fNACPs) and a custom-built, hand-held instrument or "acoustic pipette" that delivers sound waves to the blood samples inside.

Thome designed the fNACPs (essentially cell-sized rubber balls) to be customized with functional coatings so they recognize and capture a designated biomarker, such as an infectious virus or a protein. The particles also respond to the pressure from sound waves differently than blood cells. The acoustic pipette harnesses this unique response.

"We're basically using sound waves to manipulate particles to rapidly isolate them from a really small volume of fluid," said Thome. "It's a whole new way of measuring blood biomarkers."

When a small amount of blood is mixed with the custom particles and placed inside the pipette, sound waves force the particles to the side of a chamber where they are trapped inside while the rest of the blood is flushed out.

The remaining biomarkers, attached to the particles, are then labeled with fluorescent tags and hit with lasers to determine the amount present.

All this happens in under 70 minutes inside a device that can fit in the palm of a hand.

"In our paper, we demonstrate that this pipette and particle system can offer the same sensitivity and specificity as a gold-standard clinical test can but within an instrument which radically simplifies workflows," said Shields. "It gives us the potential to perform blood diagnostics right at the patient's bedside."

This could be particularly useful for assessing not only whether a patient has an infectious disease but also what their viral load is and how fast it is growing. The device could also potentially play a role in measuring antibodies to determine whether someone needed a booster shot or not, testing for allergies or detecting proteins associated with certain cancers.

The study is a proof-of-concept, and more research is necessary before the device could be commercialized. The auhtors have applied for patents and are exploring ways to make the technology work for multiple patients at once or test for multiple biomarkers simultaneously.

"We think this has a lot of potential to address some of the longstanding challenges that have come from having to take a blood sample from a patient, haul it off to a lab and wait to get results back," said Shields.