For decades, ultrasound has been associated with diagnostics – a routine scan in a hospital room, a screen showing organs, tissues or the first picture of a baby. However, researchers are now looking at ultrasound from a completely different angle. New findings from scientists at Kaunas University of Technology (KTU) indicate that ultrasound waves may not only help doctors see inside the body, but low-frequency ultrasound directly affects blood flow – potentially opening new possibilities to support the treatment of cardiovascular disease, Alzheimer’s disease and diabetes, reducing the need for invasive procedures in the future.
What surprised the researchers the most was that the ultrasound did not affect the blood in a single way. Their study showed that different sound frequencies can produce opposite effects on red blood cells: they can either encourage the cells to clump together or break them apart into individual cells.
Non-invasive way to improve oxygen exchange
Red blood cells, also called erythrocytes, naturally tend to form reversible clumps known as aggregates. This process affects the viscosity of the blood – a property closely related to circulation and the transport of oxygen throughout the body.
When erythrocytes are aggregated under the influence of high-frequency ultrasound, blood viscosity increases, blood pressure and pulse may increase, and oxygen exchange becomes less efficient.”
Vytautas Ostaševičius, lead author of the study, KTU professor
The researchers found that high-frequency ultrasound creates standing acoustic waves that drive red blood cells toward areas of low pressure, promoting aggregation.
Low-frequency ultrasound, however, creates traveling acoustic waves that generate shear forces capable of separating aggregated red blood cells into individual cells.
Experiments have shown that low-frequency ultrasound can separate aggregates of erythrocytes into individual cells. “As far as we know, this effect has not been demonstrated before,” says Ostaševičius, director of the KTU Institute of Mechatronics.
When erythrocytes separate, gaps appear between them, which reduce blood viscosity, and the entire surface of the cell can participate in oxygen exchange.
The idea for the research emerged during the COVID-19 pandemic, when scientists looked for non-invasive ways to support patients facing severe respiratory complications.
“At that time, there was an urgent need for treatments that could help patients quickly and without medication. We were interested in whether ultrasound could intensify the interaction between hemoglobin and oxygen in the lungs,” says Ostaševičius.
To investigate this, the team separated the patients’ blood into several hundred samples, which were exposed to ultrasound of varying intensity and revealed the specifics of erythrocyte dissociation. In studying the propagation of ultrasound in biological tissues, the team used digital twins to develop a low-frequency ultrasound transducer capable of sending acoustic signals about four times deeper into biological tissues than conventional devices. This technology is now protected by an international patent.
Potential applications in the treatment of Alzheimer’s disease and diabetes
Although the technology remains in an early research stage, the researchers believe that low-frequency ultrasound could eventually be applied to many medical fields where blood circulation and oxygen delivery play an important role.
One of the areas being investigated is the treatment of cancer. Since tumor tissue is often mechanically weaker than surrounding healthy tissue, traveling acoustic waves are being explored as a way to help selectively affect tumor structures. However, this idea is still at an early research stage.
“Low oxygen levels in tumors remain one of the biggest challenges in cancer treatment. If tissue oxygen supply can be improved locally, it can help increase the effectiveness of certain treatments,” says Ostaševičius.
The researchers also see potential in the treatment of Alzheimer’s disease, where the approach is being discussed as a possible future way to temporarily open the blood-brain barrier and, in the future, improve targeted drug delivery to brain tissue.
According to Professor Ostaševičius, the technology could also support the treatment of diabetic foot ulcers, where impaired circulation makes wound healing significantly more difficult. “Using ultrasound, it may be possible to improve blood flow to affected tissues,” he says.
Additional future applications may include targeted drug delivery and supportive therapies for cardiovascular and pulmonary diseases.
Although the technology is still experimental, the researchers believe their findings expand the understanding of ultrasound as more than just a diagnostic tool. “Our work shows that ultrasound can mechanically affect blood properties. This opens up possibilities for future non-invasive treatments that may one day complement existing drug-based and surgical treatments,” says Ostaševičius.
Source:
Journal Reference:
