Neurosurgery is an extremely complex procedure, primarily because the brain is a highly intricate organ with countless functional structures tightly interwoven, and navigating and performing treatments within the brain presents significant challenges. A team from The Chinese University of Hong Kong has developed microrobots created using a patient's own blood, capable of traversing the most convoluted regions of the brain. These fibrous, micron-thick microrobots, resembling "red worms," can directly deliver chemotherapy drugs to tumor sites, offering the potential for improved brain tumor treatment.
Currently, all brain tumor treatment options carry risks. Surgical resection involves extremely high risks, while radiation therapy may inadvertently damage fragile brain tissue. Chemotherapy is the third common treatment method, but hindered by the blood-brain barrier, it is difficult to deliver a sufficient drug dose to the brain. Tumors hidden deep within the brain are particularly challenging, involving hard-to-reach areas or proximity to critical functional regions such as the brainstem, thalamus, or behind the orbits, requiring extra caution.
A team led by Professor Zhang Li from the Department of Mechanical and Automation Engineering at CUHK has developed microrobots made from a patient's own blood, capable of moving within narrow spaces as small as two millimeters. Specifically, the team extracts fibrinogen from blood and combines it with hydrogel, a highly flexible material, resulting in microrobots whose stiffness closely resembles that of brain tissue. This provides greater elasticity for the robots' movement, allowing them to navigate through the brain's most complex regions without causing observable damage and further reducing the risk of immune rejection.
Additionally, the blood-hydrogel microrobots are embedded with magnetic nanoparticles, meaning their activity can be observed via X-ray imaging technology, and they can be controlled in real-time through programming using an external magnetic field.
Moving via cerebrospinal fluid for easier control
"This approach enables the microrobots to achieve various modes of movement, including rolling, crawling, and swinging, and allows for adaptation to specific environments," Prof. Zhang explained in an interview. By dynamically adjusting the direction and strength of the magnetic field, the robots can adapt to the brain's complex structures, ensuring precise and safe navigation.
"Surgeons can guide the robots to the tumor site, and then use a powerful external magnetic field to make the microrobots split, precisely releasing the chemotherapy drugs at the required location."
The professor particularly noted that the blood-hydrogel microrobots move via the cerebrospinal fluid, which is superior to using blood vessels. Blood flow speed can reach 30 centimeters per second or higher, whereas cerebrospinal fluid flows at a rate of only 0.3 to 1 centimeter per second, making it easier to control the microrobots. This method also effectively bypasses the obstruction of the blood-brain barrier and the problem of rapid drug loss in the bloodstream.
Targeted drug delivery to reduce side effects
"Compared to traditional therapies, the localized, targeted delivery of chemotherapy drugs is significantly more effective. It can release a higher drug concentration in the required area while minimizing impact on other regions, thereby reducing side effects," Prof. Zhang shared. This technology is especially suitable for treating hard-to-reach or concealed tumors. It could be applied to treat most brain tumors and even tumors in other deep-seated organs.
In the study, the microrobots successfully inhibited brain tumor growth in pigs. Prof. Zhang stated that the team's next phase is to optimize the design and functionality of the soft microrobots. "We are improving the fiber structure to enhance movement capability and drug delivery function, and to improve precision and efficiency. We are also exploring and integrating advanced imaging and control system functionalities to enhance real-time tracking and remote operation effects," aiming to advance towards clinical application in the future.
(Source: Wen Wei Po; Journalist: Ji Wenfeng; English Editor: Darius)
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