Ultrasound waves of scaled intensity and frequency have shown promise in breaking apart different types of cancer cells without harming healthy blood cells.

The waves are able to exploit the physical and structural properties of tumour cells, and could eventually offer a safer treatment option for cancer patients.

The research, which was carried out at the California Institute of Technology (Caltech) and City of Hope Beckman Research Institute, has now been published in Applied Physics Letters.

Caltech PhD candidate David Mittelstein said: “This project shows that ultrasound can be used to target cancer cells based on their mechanical properties.

“This is an exciting proof of concept for a new kind of cancer therapy that doesn’t require the cancer to have unique molecular markers or to be located separately from healthy cells to be targeted.”

The research team found that ultrasound applied at a frequency of 0.5 – 0.67 MHz and a pulse duration of >20 milliseconds caused selective disruption of breast, colon, and leukaemia cancer cell models.

This occurred without significant damage to healthy immune or red blood cells, but the cancer cells were vulnerable to the ultrasound and specific frequencies.

Mittelstein said. “There are many questions left to investigate about the precise mechanism, but our findings are very encouraging.”

Ultrasound therapies are regularly used to destroy tumours without invasive surgery, in the form of high-intensity beams which heat and destroy cells or via contrast agents injected prior to ultrasound. However high-intensity beams can destroy healthy cells as well as cancerous ones and contrast agents don’t work for many tumours.

Now, the researchers hope their work will lead other teams to explore this kind of therapy, known as oncotripsy, as a treatment for cancer. They hope that it could one day be used alongside chemotherapy, immunotherapy, radiotherapy and surgery to treat malignant tumours.

Further research will now be needed to gain a better understanding of what specifically occurs in a cell impacted by this form of ultrasound.