The new technology has so far only been tested on rabbits. However, with further research, it could become an alternative to stents and other devices currently used to stabilize aneurysms.
Implants can stop bleeding caused by an aneurysm when the artery wall weakens and swells. But this treatment can also cause problems, such as rebleeding or the procedure only partially repairing the aneurysm. Blood thinners may also need to be taken indefinitely to prevent clots, says University of Edinburgh researcher Qi Zhou, co-author of a new paper describing the nanorobots.
“Our remotely controlled magnetic nanorobots are a more precise and safer way to rapidly seal brain aneurysms without the use of implants,” says Zhou. “They can also reduce the tedious task for surgeons of inserting a long and thin microcatheter through complex networks of blood vessels.”
Aneurysms can form in any artery in the body. Once formed in the brain, they can burst and cause a stroke. In order to create a new solution to these dangerous phenomena, Zhou and his colleagues created nanobots with a diameter of just 295 nanometers. By comparison, a typical virus is about 100 nanometers in diameter, while most bacteria reach 1,000 nanometers in diameter.
Each robot consists of a magnetic core, an aneurysm-treating clotting agent called thrombin, and a coating that melts easily when heated to release the drugs.
“Using a magnetic field, the nanorobots can be directed to the aneurysm,” says Q. Zhou. “Then, using concentrated heat, the coating melts, the drug is released, and the aneurysm is blocked from circulation.”
This heat is supplied by an alternating magnetic field, which essentially creates friction by disrupting the alignment of particles exposed to the field. The temperature is kept below 50 degrees Celsius – so as not to damage the body tissues.
The idea is that cardiovascular surgeons could use a microcatheter to launch these nanorobots into the bloodstream in front of an aneurysm. This would prevent doctors from having to dig too deeply into the small blood vessels of the brain.
In the new study, published in the journal Smallthe researchers first tested the biocompatibility of the nanorobots with human cells in laboratory dishes. A biocompatible material can be introduced into living tissues without causing damage or unwanted side effects. They also conducted preliminary animal studies by treating three rabbits with artificially induced aneurysms in the carotid arteries that supply the brain and head.
During the two-week follow-up period, three rabbits remained healthy and their aneurysms were occluded.
In the future, this technology will need to be tested on larger animals that better mimic the human body, says Q. Zhou. The researchers will also need to test the safety and effectiveness of the nanorobots in long-term studies. In the rabbit tests, the aneurysms were located at a shallow depth, so the team will also need to improve the magnetic guidance system – to better target the robots to aneurysms deep in the brain.
“There is still a lot of work to be done, but we believe that this technology can fundamentally change the way brain aneurysms are treated,” says the scientist.
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2024-09-06 21:30:41