The world's smallest medical robot can help fight cancer and serve other functions that conventional surgical methods can’t.
Robots don’t need to be giant to be useful, and an impactful nanoscale robot developed by researchers at the University of Texas at San Antonio shows just how size doesn’t really matter. The medical robot is so small that it isn’t visible to the human eye. That’s its advantage. The tiny robot can help fight cancer and serve other functions that conventional surgical methods can’t.
The 120-nanometer spherical robot (for comparison, a strand of DNA is roughly 2 nm wide, while a human hair is about 90,000 nm wide) which was recently entered in to the Guinness World Records as the “smallest medical robot,” has promise.
The tiny robots consist of nanocomposite particles made from multifunctional oxide materials that can be controlled remotely by an electromagnetic field. Once functional, these robots interact with biological cells, giving them medical potential. They can manipulate cells in specific alignments, move cells to other locations, or deliver medicine to cells. Those capabilities could be useful in personalized medicine or treatment of cancer.
Cancer can be treated by controlled cell electroporation (a technique that uses a pulse of electricity to open a cell membrane to introduce drugs, chemicals or DNA to the cell) and targeted drug delivery. The UTSA team demonstrated the former using the nanorobots and the latter is being developed in the nanocomposites’ functionalization.
“Nanorobots employed for targeted cancer cell drug delivery can potentially eliminate the complexities and massive side-effects to cancer patients caused by non-discriminative radiation and chemotherapy,” says Dr. Ruyan Guo, professor of electrical engineering at UTSA.
Alzheimer’s and Parkinson’s can be treated by the targeted cell transport for vascular repair or by regenerating or repairing impaired neural pathways.
“Our nanorobots are potential transporters, delivering modified cells and submicron-sized surgical tools conducting targeted in-vivo vascular repairs, possibly with micrometer precision and reaching those places where surgical operations are not an option,” Guo says.
The researchers first studied the magnetoelectric effect towards developing applications for advanced sensors and actuators. Then they explored the fabrication of nanocomposite materials and studied their suspension in solutions.
“We learned that the magnetic response and their electric surface potential vary according to the size of the core and the layer thickness of the shell,” he says. “Once we observed that the movement can be controlled by magnetic field, we realized that it could be utilized for targeted drug delivery and more.”
The researchers conducted experiments to demonstrate and understand the robots’ interaction with biological cells. Their non-toxicity and bio-compatibility was confirmed by testing on human and rat cells.
A “wireless” sensing mechanism of the nanorobot drives the movement. Once the core senses the magnetic field, it tries to align, expanding or contracting in the process. It sends a pressure pulse, which prompts the nanocomposite’s movement.
“The trajectory of the movement is different for a DC magnetic field or AC magnetic field. It can do ‘work,’ like transporting cells, if the combined force overcoming the friction of the suspension liquid, is non-zero,” Guo says. Non-zero in this case refers to a calculated value that helps the robot move in a specific direction based on the coupled effect.
The researchers plan on exploring the benefits of the robot. One application could be in using the robot to completely eliminate chemotherapy, and also in Alzheimer’s disease to replace lost cells in a brain.
Agam Shah is Associate Editor for Mechanical Engineering magazine.
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