Miniaturised soft inflatable actuators for biomimetic ciliary propulsion

Edoardo Milana, PhD
Assistant Professor
University of Freiburg, Germany
Research interests
Soft Robotics, Bioinspired Systems, Microengineering, Applied Mechanics

Ciliates, a large group of microorganisms that live in environments characterized by low Reynolds numbers, use ciliary propulsion to displace themselves or the surrounding fluid. Their bodies are covered by arrays of beating cilia, slender organelles working in unison to induce net flows. Natural cilia beat collectively (metachrony) and individually (nonreciprocal motion) in an asymmetric way to be able to set a fluid in motion where viscous forces are predominant. The artificial cilia here presented consist of array of miniaturized elastic inflatable bending actuators. The eccentric location of the inflatable chamber with regard to the actuator’s symmetry axis determines the bending deformation of the actuators, which are microfabricated with silicone elastomers. By individually controlling each inflatable segment, we are able to mimic the nonreciprocal motions of biological cilia and demonstrate the influence of such movements on low Reynolds fluid propulsion. Artificial cilia are anticipated to play key roles in applications where Reynolds numbers are very small, such as pumps or mixers in microfluidics or operations in highly viscous fluids.

Edoardo Milana studied mechanical engineering and nanotechnology at Sapienza University of Rome. In 2020 he obtained his Ph.D. in engineering science at KU Leuven, with his research on artificial cilia and soft robotics. In 2019, he was a visiting researcher at the University of Milan, working on electroactive polymers. He then worked as postdoctoral researcher at the DLR – German Aerospace Center and the University of Freiburg. Currently, he is Assistant Professor in Soft Machines at the Department of Microsystems Engineering (IMTEK) of the University of Freiburg.