For some time now, robots have been breaking ground that it is difficult for human beings to reach. They provide data from the outer reaches of the solar system, from far away planets or from the depths of the oceans. Now they are to be sent on a journey of discovery into a far smaller, though not less important, region–that of the human body. Because even within our own organism locations exist that physicians and surgeons can reach only with difficulty or not at all.

Professor Bradley Nelson and his team at the ETH Institute of Robotics and Intelligent Systems develop microscopic robots, conceived specifically for biomedical intervention (1). The scientists have succeeded in creating the smallest robot of its kind so far. "We have managed to make components that are not wider than four human hairs laid side by side," says Bradley Nelson. The size of the machine is naturally decisive for its use in minimal invasive surgery. For example, it is only possible to transport drugs in a precise manner to their designated location without seriously injuring the patient with superfine components.

Little man in the eye

The thought of having a robot injected to one's eye probably makes most people feel squeamish. Doesn't such an intervention carry a high risk? Bradley Nelson emphasises that research stood at the beginning of the use of microscopic robots in surgical intervention. "At the moment, the focus of our research is directed towards eye surgery," explains the professor. This special area was chosen for practical reasons. "Microscopic robots can be steered with relative ease around this organ," he says. Moreover, ophthalmologic surgeons were still dependent on relatively thick needles and instruments. "This is why we can say that by using a robot we can minimise patients risk in connection with eye operations."

Mini-submarine on a medical mission: Visualisation of a tiny robot that has been injected into the eye at the moment it delivers the drugs it carries (Picture: Institute of Robotics and Intelligent Systems, ETH Zurich) large

"The application we're testing at the moment is the dispensing of a drug via the veins of the retina, which aren't wider than a human hair," explains Bradley Nelson. Constructing a robotic system that can function inside the human body is a huge scientific challenge. Research in the area of "BioMicroRobotics“ has only become possible with the scientific ability of combining micro and nano-technologies with medical robotics. In contrast to traditional robots powered by batteries or an electric cable, microscopic robots draw their energy from an external magnetic field.

Owing to the high complexity of the microscopic robots, ETH scientists are currently concentrating on two points, namely on the construction and design of the apparatus including everything involved in the control of the machine within the human organism. At present there are four different, cube-shaped robots whose application depends on the type of medical intervention.

Medicine for the future

For Bradley Nelson "BioMicroRobots“ represent a technology that could be a signpost for future medicine. This is why their application should be used in very diverse areas of medicine. "We have regular discussions with cardiologists, are testing the employment of a robot in human ears and investigating how they could be used in the treatment of tumours," he says. Soon, however, it won't only be their use in various organs that scientists will be working on."We are continuously enhancing the robots. Our goal is to make the individual components as small as possible while making them as easy as possible to steer," says the Professor for Robotics and Intelligent Systems. "Only in this way can we guarantee patients the best possible treatment with as little trauma as possible."