A new class of sound wave has been developed for the first time in 50 years that looks set to revolutionise the use of stem cells in medical treatments.

Created by acoustics experts from RMIT University in Melbourne, Australia, the sound waves – known as “surface reflected bulk waves” – are gentle enough to manipulate stem cells without causing damage, something that has not previously been possible with sound waves.

The researchers have already used the technology to significantly improve the efficiency of an advanced nebuliser device developed at RMIT, which delivers medicine directly to the lungs.

“We have used the new sound waves to slash the time required for inhaling vaccines through the nebuliser device, from 30 minutes to as little as 30 seconds,” said study co-author Dr Amgad Rezk, from the Micro/Nano Research Laboratory at RMIT.

“But our work also opens up the possibility of using stem cells more efficiently for treating lung disease, enabling us to nebulise stem cells straight into a specific site within the lung to repair damaged tissue. This is a real game changer for stem cell treatment in the lungs.”

Surface reflected bulk waves are known as such due to their combination of bulk sound waves and surface sound waves.

Bulk sound waves cause an entire material to vibrate as one, an effect that the researchers liken to holding a carpet at one end and shaking it.

By contrast, surface sound waves only cause the surface of a material to vibrate, with the researchers comparing the effect to waves in an ocean.

By combining the two, the researchers have created a sound wave class that is far more powerful than its component wave types.

“The combination of surface and bulk wave means they work in harmony and produce a much more powerful wave,” said Rezk.

“As a result, instead of administering or nebulising medicine at around 0.2ml per minute, we did up to 5ml per minute. That’s a huge difference.”

The researchers have created a device to utilise surface reflected bulk waves in medical devices with the rather epic name HYDRA.

This passes electricity through a piezoelectric chip, converting it into mechanical vibration, or sound waves, that can break liquid into a spray so it can be inhaled.

“It’s basically ‘yelling’ at the liquid so it vibrates, breaking it down into vapour,” explained Rezk.

HYDRA has been used to improve RMIT’s advanced nebula, known as Respite, which can be used to deliver a wide range of drugs into the body without the need for pills or injections.

For sufferers of asthma and cystic fibrosis, the device can deliver highly precise drug doses, but it can also be used to provide diabetes patients with insulin, and give infants vaccines without an injection.

The details of the research have been published today in the journal Advanced Materials.