Researchers at the University of Alberta (Edmonton, AB, Canada) are developing cutting-edge robots so tiny that they are invisible to the naked eye but are capable of traveling through the human body to remove blood clots in the brain. These tiny robots, or "actuators," are designed to swim through the bloodstream to target and destroy tumors, disintegrating harmlessly after their task is accomplished.

These microrobots are engineered to detect a specific chemical emitted by a brain tumor and navigate toward it to encapsulate the tumor and halt its growth. To make this possible, a collaborative effort between engineers and medical experts at the University of Alberta is underway to develop biocompatible materials. The team has successfully demonstrated the construction of such actuators using carbon nanotubes. These nanotubes, each only five nanometres thick—10,000 times thinner than a strand of human hair—are placed on a silicon wafer. The entire assembly can measure as little as five microns, which is about one-twentieth the diameter of a human hair. These actuators are activated by an electric charge that causes them to move in specific ways, such as bending or opening and closing, to perform precise tasks.

For instance, sending an electric signal triggers an electrochemical reaction at the surface of the micro-actuator, causing it to swell—a mechanism used to open and close its end. Although still in the early stages of development, this technology might enable the micro-actuator to bend and eventually walk or swim. In the future, these microrobots could be used non-invasively for medical procedures like colonoscopies, pelvic exams, or blood tests. Additionally, the team is investigating the integration of nano-scale computer chips into these actuators and is also developing tiny batteries that provide just enough power for a single task.

“If they had processors onboard, that would be a game changer,” said Mahdi Hamidi, a professor in the Department of Mechanical Engineering at the University of Alberta who is working on the next-generation robots. “The microrobot could be connected to the internet, and you could perhaps change the program during its mission.” 

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