Ultrasound and nanobubbles combine to deliver drugs

In collaboration with the Press Association

US scientists have discovered a way to explode microscopic drug-filled bubbles inside the body by using high-energy soundwaves.

The technique could one day lead to the precise delivery of cancer drugs to a patient's tumour, reducing the side-effects of chemotherapy.

The research team, based at the University of Utah, inserted the chemotherapy drug doxorubicin into microscopic plastic 'nanobubbles' and injected these into mice with human breast cancer tumours.

The bubbles travelled through the bloodstream, and the researchers followed their progress using ultrasound. They found that the bubbles accumulated in the tumour, forming larger 'microbubbles'.

In an ingenious twist, the researchers were then able to use the ultrasound to 'pop' the bubbles, releasing the drug into the tumour.

Dr Natalya Rapaport, a researcher in the university's department of bioengineering, told Reuters news agency: "When these bubbles accumulate, I give strong ultrasound radiation to the tumour to blow them up. Then the drug gets out of these bubbles locally at the tumour site."

The researchers found that delivery of the drug in this way was more effective at blocking tumour growth than other nanoparticle-delivery methods.

"A technology that combined ultrasound imaging with ultrasound-mediated nanoparticle-based targeted chemotherapy could therefore have important applications in cancer treatment," the researchers wrote in the Journal of the National Cancer Institute.

The researchers hope to start further animal studies later this year and note that more research will be needed before the technique's potential as a cancer treatment can be determined.