Ultrasound-Activated Particles Soften Tumors, Making Cancer Treatment Safer and More Effective

University of Colorado Boulder researchers have developed a new approach that could make solid tumors easier to treat while reducing harm to healthy tissue. The method combines high-frequency ultrasound with sound-responsive microscopic particles designed to soften tumor tissue, potentially improving how well therapies can reach cancer cells.

Cancer remains a leading cause of death in the U.S., and while treatments such as chemotherapy and ultrasound can be effective, they often come with a major drawback: damage to healthy tissue. The CU Boulder team aimed to address that challenge by changing the physical structure of tumors themselves.

In a new study, researchers paired ultrasound waves with a particle that vibrates and pulses in response to sound. When exposed to high-frequency ultrasound, the particles vibrate rapidly enough to vaporize surrounding water, forming tiny bubbles. The particles are made of silica and coated with a fatty molecular layer.

To test the approach, the team added the particles to tumor tissue cultures. When ultrasound was applied, the particles altered the tumor structure. In 3D tumor cultures, the treatment reduced levels of certain proteins surrounding tumor cells—effectively lowering the protein content that helps give tumors their stiffness—resulting in softer tissue.

Andrew Goodwin, associate professor of chemical and biological engineering at CU Boulder, compared tumors to a crowded city: “Tumors are kind of like a city. There are highways running through, but it's not laid out very well, so it's hard to get through.” He added, “Are there ways we can improve these lines of transport so the drugs can do their job?”

The researchers suggest that softening tumors may also lower treatment risks, potentially reducing the amount of chemotherapy or the intensity of ultrasound needed to achieve therapeutic effects. As researcher Curry noted, “A major limitation in many tumor treatments is delivering sufficient therapeutic doses without damaging healthy tissue.”

Goodwin believes the strategy could be beneficial for prostate, bladder, and other localized cancers, and he hopes it can integrate with growing advances in focused ultrasound: “The technology for focused ultrasound has come a really long way in the last decade.”