Artificial Cilia–Bridging the Gap with Nature

Abstract Human ingenuity has found a multitude of ways to manipulate fluids across different applications. However, the fundamentals of fluid propulsion change when moving from the macro‐ to the microscale. Viscous forces dominate inertial forces rendering successful methods at the macroscale ineffective for microscale fluid propulsion. Nature however has found a solution; microscopic active organelles protruding from cells that feature intricate beating patterns: cilia. Cilia succeed in propelling fluids at small dimensions; hence they have served as a source of inspiration for microfluidic applications. Mimicking biological cilia however remains challenging due to their small size and the required kinematic complexity. Recent advances have pushed artificial cilia technology forward, yet discrepancies with natural cilia still exists. This study identifies this gap by analyzing artificial cilia technology and benchmarking them to natural cilia, to pinpoint the remaining design and manufacturing challenges that lay at the basis of the disparity with nature.