Medical microrobots score the Breakthrough of the Year

The grand finale of the Falling Walls Conference on 9 November in Berlin had to be held online this year due to the Covid-19 situation. The Breakthroughs of the Year were awarded in ten categories. To mark the 31st anniversary of the fall of the Berlin Wall, the organisers wanted to highlight the “walls” in science and society that would be the next to fall. The juries selected ten winners in each category from a pool of more than 600 finalists, including no fewer than five researchers from ETH Zurich (see box).

ETH President Joël Mesot, who this year chaired the ten-member jury in the “Engineering & Technology” category, addressed the attendees of the award ceremony: “In times like these, it is particularly important for us to bring attention to bold research ideas that address societal challenges. The World Science Summit provides an important stage on which to celebrate the creativity of researchers from all over Europe.” This year, the unanimous choice in the “Engineering & Technology” category was Metin Sitti, who has repeatedly attracted attention in recent years with his surprising and innovative developments in microtechnology and robotics. Sitti is currently a professor at the University of Koç in Istanbul and Director of the Max Planck Institute for Intelligent Systems in Stuttgart. This May, he was also appointed an affiliated professor in the Department of Information Technology and Electrical Engineering at ETH Zurich.

Microrobot on a fantastic voyage

Sitti cites the 1966 cult film Fantastic Voyage as an important inspiration in his research career. In the film, a submarine, and its expedition team, is shrunk down to such a size that it can be injected into the bloodstream of a patient and sent on a journey through capillaries and organs. The aim is to break up a blood clot in the patient’s brain. For Sitti, what still sounds like science fiction to most people illustrates the future of medicine – apart from shrinking the researchers, of course. Today, he develops tiny robots for medical purposes that are practically invisible to the naked eye. And if all goes to plan, they too will one day circulate in our bloodstreams in order to diagnose disease and, where possible, treat it immediately.

Sitti grew up in Turkey. As a child, he spent a lot of time observing animals and studying their movement and behaviour. Nevertheless, it was not biology but engineering that he chose to study at Boğaziçi University in Istanbul. He completed his doctorate at the University of Tokyo in Japan. After a three-year research stint at the University of California, Berkeley, he researched and taught as a professor at Carnegie Mellon University in Pennsylvania from 2002 to 2014. “Microtechnology and robotics gave me the opportunity to turn my fascination with nature and its creatures into an important part of my work,” says Sitti. “It was a dream come true for me.”

Innovation using geckos as a model

For example, in the development of a new generation of adhesive and bonding material, he drew inspiration from the feet of geckos. Thanks to the adhesion produced by millions of fine hair-like setae, the animals can walk upside down on a pane of glass. Sitti and his team have developed a polymer film inspired by these properties. The material has mushroom-shaped tips measuring only a few micrometres in size, the intermolecular forces of which give the film exceptionally good adhesion and durability. This is in contrast to conventional adhesive materials, where the effect is based on a chemical reaction in a humid environment. In 2009, Sitti founded the spin-off nanoGriptech, which develops adhesive and bonding materials for applications in medicine, sports equipment, semiconductors and robotics. Sitti is always interested in the practical applications of his research: at present, twelve patents in his name are pending, with 15 more in the pipeline.

Sitti’s current research at ETH Zurich focuses on bio-inspired micro- and nanorobotics, and in particular the coupling of microrobots with magnetic resonance imaging (MRI). This should one day make it possible to precisely map, monitor and control the wireless robots in the body. He recently presented a biocompatible microrobot just 3.7 millimetres long, 1.5 millimetres wide and 0.18 millimetres thick. It can move around the body in seven different ways, including rolling, swimming and jumping. Microorganisms served as a model. The robot is equipped with tiny magnets that can be excited externally in different ways via an electromagnetic field. The intelligence of such a microrobot is based primarily on its physical structure, the material used and the ability to self-organise, rather than on powerful computers as is the case with larger robots. “It is the first time that a robot of this size combines so many movement capabilities,” says Sitti. “This would allow it to move in practically any part of our body.”

His team has also recently developed a soft capsule just a few micrometres in diameter with which liquid active ingredients can be applied with the highest precision to the target site in the organism by means of an external impulse. This may enable non-invasive biopsies. However, due to exacting safety requirements, a great deal of research and development is still needed before the robots can be used for increasingly personalised medicine. One of the greatest challenges is the measured and precise control of robots in turbulent body fluids and pulsating organs. Sitti estimates that it will take ten years before the first clinical applications in humans are possible. However, he is already convinced of the advantages of medicine supplemented by micro- and nanorobotics: “We are on the way to a medicine that can detect disease earlier and treat it with far fewer side effects.”