Over the past few decades, performing complicated operations inside the human’s vascular system and other cavities has been a huge challenge for surgeons across the globe. That is why a surprising number of scientists have put much effort into creating practical medical nano-robots. With a great deal of experimentation and some trial and error, this goal has been achieved with honours in Hong Kong.

Inspired by swarming behaviour in the natural world, Prof Zhang Li, the Associate Professor of the Department of Mechanical and Automation Engineering at the Chinese University of Hong Kong (CUHK), led his team to conduct research into nanobots, in the form of millions of magnetic nanoparticles. This research is funded by Innovation and Technology Commission, Hong Kong Research Grants Council and CUHK T Stone Robotics Institute.

Throughout the research process, Zhang’s team considered “miniaturisation” as a key in designing a nano-robot. The batteries of robots could be made very fine; however, other electronic components like controllers and sensors are not so easy to reduce in size. This limits the robots’ ability to get through the hard-to-navigate spaces in human body.

With this concern in mind, Zhang’s team deployed a different approach towards “miniaturisation”. It used a Rapidly Oscillating Magnetic Field, which was emitted by a peripheral coil, to change the shape and direction of millions of nanoparticles at the same time. By tuning the amplitude and frequency of the magnetic field, the microscopic swarm made up of these nanoparticles can be made to split up, re-join and even move through a maze.

The team hopes to apply the magnetic microswarm technique to treat diseases in the vascular system, such as stroke. At this moment, the team is working hard to overcome different kinds of problems. For instance, the magnetic nanoparticles can only move in a two-dimensional space whilst the human blood vessel is a three-dimensional structure. In addition, the nanoparticles are always engulfed by the white blood cells inside the human body.

Notwithstanding some challenges, Prof Zhang feels optimistic and anticipates that nanobots will definitely enter the mainstream medical market within five to ten years.