Imagine listening to your favorite song and swaying your body uncontrollably to the rhythm. There is an expression for this sensation, and it is fitting: You can feel the music in your bones.
As it turns out, there is an element of truth in the phrase.
According to a new study in the scientific journal Small, a team of researchers at RMIT University in Melbourne, Australia used high-frequency sound waves to treat bone injuries and diseases — a potentially revolutionary treatment. The trick is to find stem cells — that is, generalized cells which can be turned into more specialized cells — and then bombard them with those sound waves. When the researchers did this in the right way, those stem cells turned into bone cells. Significantly, they did so even when the stem cells were derived from fat, where they can be extracted much less painfully than through bone marrow. Previous attempts to grow bone with stem cells used bone marrow.
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"The high frequency sound waves generate a pressure, which pushes across the stem cells," Dr. Amy Gelmi, co-lead researcher and a Vice-Chancellor's Research Fellow at RMIT, told Salon by email. "It's this 'pushing' force which triggers the stem cells to begin their journey to turn into bone cells. Stem cells are very responsive to physical forces around them, and we found that the force exerted by our high frequency sound waves was ideal in 'convincing' the stem cells to turn into bone quickly and efficiently."
The research could have many practical applications. One of the main challenges with regenerating lost bone tissue is making sure that it creates a bone with adequate structural soundness. This approach could make that possible.
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"We plan to start using the device to 'condition' stem cells so they are ready to turn into bone cells, and then try a few ways to develop bone tissue implants," Gelmi explained. "For example, like loading the conditioned stem cells into a 'bio-ink' and 3D printing a shape for the stem cells to grow into and create bone tissue."
This is not the first important work to be done with high-frequency sound waves, meaning those with frequencies above 10 megahertz. In 2020 RMIT researchers detailed a number of potential applications for the technology, from more efficiently delivering drugs to human lungs to helping the body more precisely target infections and tumors. They have already been used to help create tumor selective drug molecules and in ultrasound procedures that provide detailed images of the body.
Speaking to News Medical Life Sciences at the time, Professor Leslie Yeo explained that "we've harnessed the power of these sound waves to develop innovative biomedical technologies and to synthesize advanced materials. But our discoveries have also changed our fundamental understanding of ultrasound-driven chemistry — and revealed how little we really know."
Yeo added, "Trying to explain the science of what we see and then applying that to solve practical problems is a big and exciting challenge."
Does that mean that all of the high-frequency sound wave research has implications for people who feel a deep physical connection with certain types of sounds, such as music?
"Perhaps!" Gelmi told Salon. "The stem cells which reside in our bodies (we all have them!) respond just as much to physical sensation as they might to biochemical signals. We're learning every day about how important it is to use these physical forces in tissue engineering."
Gelmi added, "Plus, I think lab work always goes more smoothly when you are vibing to a really good playlist."
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