Professor Zhang Li shows enlarged images of his team's medical microbots that are being tested. Photo: Nora Tam

Chinese University scientists build tiny robot to battle human diseases

Chinese University team creates microbot the size of a human cell which can carry a big payload of drugs to trouble spots in the body

Andrea Chen

Chinese University researchers say they have designed a micro robot no bigger than a human cell that can carry a payload of drugs much greater than previous models and could replace the risky operations now needed for brain and eye diseases.

The cage-like device, 100 microns long and 40 wide, is small enough to be injected into the body without leaving a wound and is guided wirelessly with an electromagnetic field.

Zhang Li, assistant professor in the university's mechanical engineering department, said comparing the device to the earlier spiral micro robots, or microbots, designed overseas was like comparing a truck to a car.

"A microbot is like a vehicle that ships drugs directly to the affected area. And I want to design a truck, not a car," Zhang said. He has been working on microbot technology for seven years.

He noticed the models available on the market could load very limited amounts of drugs, and so decided to modify them by changing the shape so they could contain more.

The new microbot can be used to precisely direct drugs to a specific part of the human body, offering alternatives to invasive treatment for brain and eye diseases like stroke and retinal degeneration.

"If we can inject thousands of these microbots carrying drugs into the human body in between vertebral columns and direct them to the affected area in the brain, we may be able to cure strokes without an operation," said Zhang.

To enable wireless control, Zhang's team made the model magnetic by coating the parts of it with a thin layer of nickel. Co-operating with institutes in South Korea and Switzerland, the team proved in lab tests that the microbot could be directed with minute accuracy by an external magnetic field. In a laboratory test where the team cultivated human kidney cells in the microbot model, the cells grew and even interacted with the model - a sign that the model was compatible with the cells, Zhang said.

The university is testing the microbot on rabbits and mice, but Zhang said it might take decades until the technology was developed enough to be tested on humans. "Tracking the microbot is a huge challenge. It will be very dangerous if we lose track of the model after injecting it into a human body," he said.

Nuclear and magnetic resonance devices are commonly used to track microbots, but the resolution of the available devices was not high enough to track the new model, Zhang said.

His team is working with experts to improve the tracking technology.


This article appeared in the South China Morning Post print edition as: Scientists build tiny robot to battle human diseases