Cancer can be a tricky foe, so the best way to fight it might not be with a direct attack, but to cut off its supply lines. One such method, known as gas embolotherapy, involves creating tiny bubbles in the tumor blood vessels, which block the blood supply and starve the cancer out. Now, researchers from China and France have found that the technique could also deal a second blow as a drug delivery system.

The first step of gas embolotherapy involves researchers injecting droplets of a liquid into the blood vessels that feed a tumor. When an ultrasonic pulse is applied to the area, those droplets form tiny gas bubbles that clog up the vessels, blocking blood flow and suffocating the tumor. This part of the process is called acoustic droplet vaporization (ADV).

In past research, this process turned out to be more effective than was expected. Not only did the bubbles successfully cut off the blood supply, but other bubbles made their way into smaller vessels like capillaries, causing them to burst and leak, which dealt even more damage to the tumor.

In the new study, the team wanted to look closer at what was happening in the capillaries. For their tests, the researchers used samples of rat tissue in the lab, and injected droplets of dodecafluoropentane mixed with a bovine serum. Bubbles were then formed using ADV.

The team observed the bubbles lodging in the capillaries, where they built up and in some cases merged. A localized cavity was also spotted in the vessel wall, which the team says was likely caused by the bubbles rupturing the capillary.

The researchers say that this could open up a second avenue of attack against cancer. Gas embolotherapy could kill tumors by not only blocking their blood supply, but delivering drugs through the capillaries. That means the drugs could be administered directly to the tumor site, and since blood isn't circulating back out, it keeps them localized, preventing the drug from circulating through the body and harming healthy cells.

"In cancer therapy research, scientists are always interested in answering two questions: how to kill the cancer effectively and how to reduce the side effects of chemotherapeutic drugs," says Mingxi Wan, corresponding author of the paper. "We have found that gas embolotherapy has the potential to successfully address both of these areas."

The next steps for the researchers is to test the method in live rats.

The research was published in the journal Applied Physics Letters.

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