July 18, 2014
Drug delivery by means of micro robots, also called microbots, which are no bigger than a human cell may one day allow drugs to be delivered exactly where needed in the body. The nickel-coated cage-like device, 100 microns long and 40 wide, is small enough to be injected into the body and guided wirelessly with an electromagnetic field. To enable wireless control, parts of the microbot are coated with a thin layer of nickel which is ferro-magnetic.
Prof. Zhang Li of the Department of Mechanical and Automation Engineering of the Chinese University of Hong Kong led the team in co-operation with Daegu Gyeongbuk Institute of Science and Technology in South Korea and ETH in Zurich, Switzerland. They proved in laboratory tests that the microbot could be directed with minute accuracy by an external magnetic field. Additional laboratory testing where human kidney cells were cultivated with the microbots showed that the cells grew and even interacted with the microbots – a sign that the microbots were compatible with the cells.
Precise delivery of drugs to a specific part of the human body offers alternatives to invasive treatment especially for brain and eye diseases like stroke and retinal degeneration.
Prof. Zhang Li said that “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.” There are still challenges ahead. 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 added.
The university is testing the microbot on rabbits and mice, but Zhang said it might take decades until the technology is developed enough to be tested on humans. Being able to guide the microbot to the exact location knowing exactly where it is at any moment is essential, and the nickel coating would enable that to happen.