The Next Blood Testing Tech Is Here … And It Might Involve Sound Waves

A new method of isolating blood for analysis could finally help make blood testing scalable, allowing doctors to identify diseases more quickly and cheaply than with existing testing methods.

Exosomes are membrane-enclosed structures in the blood that live inside of cells. Since their discovery three decades ago, evidence has led scientists to believe that exosomes contain indicators of diseases such as cancer, Alzheimer’s disease, and multiple sclerosis.

However, the current method of isolating particles in the blood for analysis isn’t conducive to analyzing these exosomes. Components in blood samples are typically separated in ultracentrifuges, machines that spin at very high speeds.

Known as centrifugation, this spinning process separates the solid and liquid particles in blood, isolating nanoparticles like exosomes in the process. However, the force of the centrifuge is often too strong, and these very small and delicate particles end up getting damaged in the process.

But now, a team of scientists, led by Mengxi Wu, a graduate student at Duke University, may have found the key to a better method of exosome isolation: sound waves.

Since 2014, the team — spanning universities including MIT, Singapore’s Nanyang Technological University, and the Magee-Womens Research Institute at the University of Pittsburgh, among others— has been working on using sound waves to separate blood.

Initially, their research led them to create a process that would separate platelets and cells from blood. Blood cells traveling through a narrow microfluidic channel would be exposed to sound waves, which crossed at certain angles to guide different components of the cell in different directions, separating out certain parts of the cell.

By fine-tuning the angle and frequency of the sound waves to account for the length of the tube and particle size allowed, the team found that they were able to separate particles of different sizes — including exosomes.

The separation process is gentler and substantially faster than the centrifuge method, which can take hours or even days to complete. “We want to make extracting high-quality exosomes as simple as pushing a button and getting the desired samples within 10 minutes,” one of the researchers, Tony Jun Huang from Duke University, explained to Science Alert.

According to the team, the new sound wave process takes less than 25 minutes to process blood samples. However, since exosomes have only recently come into the spotlight as possible indicators of disease, there’s still more research to be done regarding their applications in health monitoring, disease diagnostics, therapeutics, and other areas. Eventually, the team hopes to combine the technology with a portable and affordable device.

The original study, “Isolation of exosomes from whole blood by integrating acoustics and microfluidics,” was published in the journal Proceedings of the National Academy of Sciences of the United States of America in August 2017. Full information is available here.