Cytophone against metastases
A laser has been created that destroys cancer cells in the blood
Nikolay Khizhnyak, Hi-News
Against cancer cells wandering through the circulatory system, scientists from the University of Arkansas have developed a new weapon: a laser beam that, when directed at the skin, penetrates into blood vessels and destroys these little killers on the spot, preventing them from accumulating in the body in the form of metastases.
In an article published in the journal Science Translational Medicine (Galanzha et al., In vivo liquid biopsy using Cytophone platform for photoacoustic detection of circulating tumor cells in patients with melanoma), it is reported that the researchers conducted successful tests of their system, accurately identifying and destroying cancer cells in 27 of 28 volunteers who took participation in clinical trials.
Effective cancer diagnosis
The developers report that their installation turned out to be 1000 times more accurate than other currently existing similar devices. This is an achievement in itself, but the researchers emphasize that their system was able to destroy a high percentage of cancer cells in real time.
With further development, experts at the University of Arkansas say, doctors will be able to get a quick, painless and non-invasive way to find and destroy cancer cells before they begin to form new tumors in the body.
"This technology has the potential to significantly inhibit the process of mesastication," says Vladimir Zharov, director of the Center for Nanomedicine at the University of Arkansas and head of the study.
The spread of cancer cells, or metastasis, is the main cause of cancer mortality. It occurs when cancer cells separate from the main focus of the disease and begin to move through the body inside the circulatory and lymphatic systems, eventually settling in other parts of the body and forming secondary tumors.
If you destroy these circulating cancer cells while still in the bloodstream, preventing them from metastasizing in other tissues, this will save many lives. Even just being able to count the number of these cells – a task that none of the previously developed devices were able to effectively cope with – will make it possible to more accurately diagnose and treat metastatic cancer.
Zharov, together with his team of specialists, tested the system they developed on people with melanoma (skin cancer). A laser aimed at a vein sends energy into the blood, creating heat. Cancer cells absorb much more heat energy than normal ones. Heat causes these cells to expand and collapse. This thermal expansion creates sound waves – a photoacoustic effect that can be registered by a compact ultrasound transducer that is placed on the patient's skin near the site of exposure to the laser beam. This device reads when tumor cells pass through the bloodstream under the laser.
Using the same laser, scientists were able to demonstrate the process of destroying circulating cancer cells in real time. The heat generated by the laser produces vapor bubbles on the surface of the tumor cell. When expanding, these vapor bubbles burst, affecting the cell, mechanically destroying it. Imagine a video game in which you destroy the bad guys with a laser. The process of destroying cancer cells here looks similar.
The purpose of this study, the developers of the laser note, was to check the accuracy of the device in determining cancer cells. But even with a low-energy diagnostic mode, the device was able to destroy a significant number of tumor cells in the blood of six patients. According to Zharov, in one patient, the device was able to destroy 96 percent of cancer cells. The scientist and his colleagues note that the efficiency of the installation can be much higher in future studies when they use the device at a higher power.
Zharov came up with the idea of this technology more than ten years ago. Since then, the scientist has been testing it on animals, demonstrating its safety to the commission of the Agency of the US Department of Health and Human Services (FDA), which issued permission for clinical trials of the installation on humans. Zharov claims that this device is the first non–invasive diagnostic device for detecting tumor cells circulating in the blood.
How else is cancer diagnosed in the blood?
To date, at least a hundred different devices have been proposed designed to monitor circulating tumor cells. However, most of these systems involve taking blood from a vein and its subsequent analysis outside the patient's body. At the same time, only one device, at least in the USA, has received approval for use by the FDA commission. It's called CellSearch, and it's about the size of an oven. At the same time, it allows you to take only small blood samples, on the basis of which it creates a general picture of cancer cells that may be present throughout the circulatory system. It is clear that due to such low efficiency, this device is not widely used in the diagnosis and treatment of cancer.
In April of this year, specialists from the University of Michigan announced the creation of a more compact device that attaches to the patient's arm and pumps blood in the body, clearing it of cancer cells. However, again, tests on dogs in laboratory conditions showed that the device is able to process only a couple of tablespoons of blood in two to three hours.
The device developed by Zharov and his team is able to process a liter of blood in about an hour. At the same time, without the need for pumping it out of the body. The sensitivity of this system is about a thousand times higher than that of the CellSearch device, the developers say. In the future, Zharov and his team plan to test their installation on more people, combining the results with traditional cancer treatment methods to see the effectiveness of this approach in solving the problem of metastasis.
By the way, the photoacoustic effect was first described by Alexander Graham Bell in 1880 when developing a photophone – a device for transmitting sounds over a distance using light. The device developed by Zharov was named "cytophone" (cytophone, from "cito" – "cell").
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