Sound diagnostic system could deliver blood test results to the bedside within an hour

Go to the doctor to provide a blood sample, and you’re usually faced with a needle and syringe, and hours or even days of waiting to get results from a lab. CU Boulder researchers hope to change that with a new portable, sound-based diagnostic system capable of providing accurate results within an hour with a simple finger prick of blood.

The team describes the system in a new paper published October 16 in the journal Scientific advances.

“We have developed a technology that is very user-friendly, can be deployed in a variety of settings, and provides valuable diagnostic information in a short period of time,” said lead author Wyatt Shields, assistant professor in the Department of Chemical and Biological Engineering. from CU Boulder. .

These findings come as scientists work to democratize diagnostic tests, which can be difficult to access for people in rural areas or developing countries and, in the case of blood tests, frightening for those who are opposite the needles.

Although existing rapid tests, called lateral flow tests, such as COVID tests or pregnancy tests, can provide a quick “yes” or “no” as to the presence of a specific biomarker or biomolecule in blood or urine, they usually cannot. say how much, and they are not sensitive enough to detect very small amounts.

Meanwhile, the gold standard of clinical blood testing, known as enzyme-linked immunosorbent assay (ELISA), is sensitive and specialized enough to detect rare or rare biomarkers, but requires expensive equipment and complex techniques, and it can take hours or days. for patients to receive the results.

The authors acknowledge that skepticism has existed in the field of biosensing since the high-profile fall of Theranos Inc., which promised as early as 2015 to detect hundreds of biomarkers with a drop of blood. Their invention works differently, they said, and unlike the now-defunct startup, it relies on systematic experiments and peer-reviewed research.

“Although what they claim to do is not possible at the moment, many researchers hope that something similar will be possible one day,” said first author Cooper Thome, a Ph.D. candidate in the Shields laboratory. “This work could be a step toward that goal, but it would rely on science that is accessible to everyone.”

Using sound waves in a new way

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

Their secret ingredients: tiny particles they call “functional negative acoustic contrast” particles (fNACP) and a custom-made handheld instrument or “acoustic pipette” that delivers sound waves to the blood samples inside.

As part of his doctorate. Work, Thome designed fNACPs (essentially cell-sized rubber balls) to be customized with functional coatings so that they could recognize and capture a designated biomarker of interest, such as an infectious virus or a protein considered a red flag for a brewing health problem. The particles also respond to the pressure of sound waves differently than blood cells. Thome designed the Acoustic Pipette to exploit this unique response.

“We basically use sound waves to manipulate particles to quickly isolate them from a very small volume of fluid,” said Thome, who specializes in the study of “acoustofluidics.”

“It’s a completely new way to measure blood biomarkers,” he added.

When a small amount of blood is mixed with the custom particles and placed inside the acoustic pipette, sound waves force the particles toward the side of a chamber where they are trapped inside while the rest of the blood is evacuated. The remaining biomarkers, attached to the particles, are then marked with fluorescent labels and hit with lasers to determine the amount present. All this happens in less than 70 minutes in a device that fits in the palm of a hand.

Corresponding to the reference clinical test

“In our paper, we demonstrate that this system of pipettes and particles can deliver the same sensitivity and specificity as a gold standard clinical test, but within an instrument that radically simplifies workflows,” said Shields, noting that this time could probably be reduced further. with future improvements. “This gives us the ability to perform blood diagnostics right at the 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 quickly it is increasing, he said. The device could also potentially play a role in measuring antibodies to determine whether or not a person needs a booster shot, testing for allergies, or detecting proteins associated with certain cancers.

The study is a proof of concept and further research is needed before the device can be commercialized. The authors have worked with Venture Partners to file patents and are currently exploring ways to run the technology on multiple patients at once (which would be useful in mobile clinics in rural areas, for example) or to test multiple biomarkers simultaneously.

“We think this has a lot of potential to solve some of the long-standing challenges of having to take a blood sample from a patient, transport it to a lab and wait to get the results back,” Shields said.