Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China
Tieshan Zhang
Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China
Gen Li
Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China
Dong Guo
Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China
Siqi Sun
Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China
Rong Tan
Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China
Jiahai Shi
Synthetic Biology Translational Research Programmes, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
Yajing Shen
Shenzhen Research Institute of City University of Hong Kong, Shenzhen 515100, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China; Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China; Cheng Kar-Shun Robotics Institute (CKSRI), Hong Kong University of Science and Technology, Hong Kong 999077, China; Corresponding author.
The unique motion styles of flagella and cilia (i.e., planar/helical waveform propulsion of flagella and two-dimensional (2D)/three-dimensional (3D) asymmetric ciliary beating), play a key role in many biological activities and inspire lots of bionic designs, especially miniature robotic systems. However, quite different to the fact in nature that microorganisms can evolve diverse motions from the homologous bio-structure (9 + 2 axoneme structure), current bionics can still not find an effective engineering solution to achieve such wisdom. Herein, by investigating the inner structure of flagella/cilia and their intrinsic driven mechanisms, we derive a unified physical model to describe the microtubules’ bending and the constructed external motions. Then, we propose a three-channel based tubular actuation concept and correspondingly fabricate an actuator via a rod-embedded casting process. By sequencing the actuation of each channel, our design can not only reproduce the diverse 2D/3D flagellar/ciliary motility in nature, but also extrapolate a variety of symmetry-breaking ciliary beating modes for effective propulsion at low Reynolds number. This study deepens our understanding of the propulsion mechanism of microorganisms and provides new inspirations for the design of biomimetic systems, which may find significant applications in a wide spectrum of engineering fields.
