Researchers from Chinese University of Hong Kong have built prototypes of a microbot, the size of a human cell, that can carry drugs into the body and eliminate the need for risk operations.

Measuring 100 microns in length and 40 microns in width, the micro-robot can be injected into the human body without leaving a wound and controlled via an electromagnetic field, according to a report by South China Morning Post (SCMP). The cell-sized bots are magnetized by a thin coating of nickel.

Citing Zhang Li, Chinese University's assistant professor for mechanical engineering, the report added it was like comparing trucks to cars. "A microbot is like a vehicle that ships drugs directly to the affected area. And I want to design a truck [to be able to carry more drugs], not a car," said Zhang, who has researched microbots for seven years. The professor said current models could only carry limited amounts of drugs, prompting him to re-engineer their form to enable them to hold more.

He said the new microbot can be used to accurately channel drugs to specific parts of the human body, providing alternatives to surgeries involving more vulnerable parts such as eye and brain to treat 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," Zhang said in the SCMP report.

The university worked with institutes in South Korea and Switzerland to run lab tests and demonstrate the microbot's ability to be controlled, within minute accuracy, by an external magnetic field. Zhang cited a lab test during which the research team cultivated human kidney cells in the microbot model, which grew and interacted with the model, he said. This indicated the model could interoperate with the kidney cells, he said, adding that tests were currently conducted on rabbits and mice.

Noting that it could be decades before the microbots were developed enough to be tested on humans, he explained: "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."