Non-invasive method to destroy tumours with nanobubbles

A new technology developed at Tel Aviv University makes it possible to destroy cancerous tumours in a targeted manner, via a combination of ultrasound and the injection of nanobubbles into the bloodstream. Unlike invasive treatment methods or the injection of microbubbles into the tumour itself, this latest technology enables the destruction of the tumour in a non-invasive manner. It has been described in the journal Nanoscale.

The researchers explained that the most prevalent method of cancer treatment is surgical removal of the tumour, in combination with complementary treatments such as chemotherapy and immunotherapy. Therapeutic ultrasound to destroy the cancerous tumour is a non-invasive alternative to surgery, but this method has both advantages and disadvantages.

On the one hand, it allows for localised and focused treatment; the use of high-intensity ultrasound can produce thermal or mechanical effects by delivering powerful acoustic energy to a focal point with high spatial-temporal precision. This method has been used to effectively treat solid tumours deep within in the body. Moreover, it makes it possible to treat patients who are unfit for tumour resection surgery. The disadvantage, however, is that the heat and high intensity of the ultrasound waves may damage the tissues near the tumour.

Dr Tali Ilovitsh and her team at Tel Aviv University sought to overcome this problem. In their experiment, which used an animal model, the researchers were able to destroy the tumour by injecting nanobubbles into the bloodstream — as opposed to into the tumour itself, as has been the case with other techniques — in combination with low-frequency ultrasound waves, with minimal off-target effects.

“Our new technology makes it possible, in a relatively simple way, to inject nanobubbles into the bloodstream, which then congregate around the cancerous tumour,” Ilovitsh said. “After that, using a low-frequency ultrasound, we explode the nanobubbles, and thereby the tumour.”

Ilovitsh explained that applying the low frequency to the nanobubbles causes their extreme swelling and explosion, making it possible to perform the mechanical destruction of the tumours at low-pressure thresholds. She added that the combination of nanobubbles and low-frequency ultrasound waves provides a more specific targeting of the area of the tumour, and reduces off-target toxicity.

“Our method has the advantages of ultrasound, in that it is safe, cost-effective and clinically available, and in addition, the use of nanobubbles facilitates the targeting of tumours because they can be observed with the help of ultrasound imaging,” she said.

Ilovitsh added that the use of low-frequency ultrasound also increases the depth of penetration, minimises distortion and attenuation, and enlarges the focal point. “This can help in the treatment of tumours that are located deep within the body, and in addition facilitate the treatment of larger tumour volumes,” she said.

The experiment was conducted in a breast cancer tumour lab model, but it is likely that the treatment will also be effective with other types of tumours and, in the future, in humans.

Image credit: iStock.com/Christoph Burgstedt

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