SUMMARY

Fluid manipulation, creating a net fluid motion is particularly difficult in creeping flow regimes due to the lack of inertial effects. Micro-organisms have therefore evolved to create complex spatially asymmetric motion with their organelles (Cilia/Flagella) to produce fluid transport, which is vital for any kind of bio-physical process. Similar asymmetric beating cilia are found in almost all life forms including humans. This work demonstrates a method for creating artificial cilia, which are potentially useful in performing similar functions. The focus of this work is to realize such cilia, study its kinematics, and demonstrate a few instances of its applications. The artificial cilia studied in this work can potentially be used in a variety of microfluidic applications such as fluid mixing, pumping, particle capture, particle transport etc.
A simple lithographic process involving two-layers of metal deposition is used to make the artificial cilia. The cilia are actuated magnetically and their asymmetric strokes in a rotating magnetic field is demonstrated. The relative importance of viscous, elastic, and magnetic forces is established and the kinematics of such cilia is studied. The artificial cilia are shown to produce a net fluid flow, and the metachronal motion in such cilia is demonstrated and analyzed. The use of such cilia for bacteria capture by immobilizing the surface of the cilia with antibodies is proposed.