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Fluid flow at sub-millimeter scale is generated by micro-organisms such as paramecium and pleurobrachia. The propulsion of fluid is due to the movement of hair-like structures called cilia covering the surface of the organism. This is one of natures most efficient ways to induce and control the flow in low Reynolds number conditions. Creating artificial structures with cilia manipulated in similar way as the natural ones would open applications in the micro-fluidics area.

Final results:

This presentation summarizes the main results achieved in the Artic project.

Press Information

Summary Poster, as published below, download Power Point file


Nature-inspired micro-fluidic manipulation using artificial cilia Philips Corporate Technologies, IMTEK, Liquids Research Ltd., University of Groningen, Politehnica University of Bucharest, University of Bath, Delft University of Technology, Eindhoven University of Technology jaap.den.toonder@philips.com
Cilia Micro-organisms such as Paramecium use tiny beating micro-hairs, "cilia", with which their surface is covered, to propel themselves through a liquid. Cilia have a typical length of 10 µm and beat asymmetrically. Inspired by this, we have developed "artificial cilia": polymer composite micro-actuators responding to an applied magnetic field. A possible application is the manipulation of fluids in microfluidic lab-on-chip devices.		The experimental set-up To test the pumping effectiveness of our artificial cilia, we developed a microfluidic cartridge in which the cilia were integrated on the floor of a microchannel. The cartridge was placed in the heart of a magnetic actuation system, which was either a set of individually addressable magnetic poles, or a rotating permanent magnet, to produce a time-varying magnetic field for cilia actuation.

Artificial cilia Our artificial cilia, made with a specially developed two-color lithography process, are thin rubber (PnBA) flaps containing dispersed super paramagnetic nanoparticles (Fe3O4). They are typically 50 to 100 µm long and 10 to 20 µm wide, and are anchored to the substrate at one end.		Particle Image Velocimetry Experiments The flow generated by the artificial cilia in the microchannel was characterized quantitatively using micro Particle Image Velocimetry (µPIV). The fluid (water) was seeded with micron-sized buoyant
	The artificial cilia are sufficiently compliant and magnetic to be actuated with a magnetic field that can be generated by a permanent magnet or an electromagnet.	fluorescent particles. By the analysis of particle images taken as a function of time, time resolved velocities of the flow field over the cilia were obtained.

Simulations of the induced flow velocity We have developed numerical models capable of simulating the flow induced by the actuated cilia, including the full interaction between the elastic cilia and the, possibly complex, fluid. Results show that, by using special magnetic actuation protocols, the cilia can be made to move asymmetrically as in nature, and generate a net flow. An out-of-phase motion of neighboring cilia, resulting in a metachronic wave, can enhance the effect. The models predicts flow rates of over 10 µl/min in a typical microfluidic channel.		From the µPIV measurements, the averaged velocity distribution over the channel height was determined. Average velocities of up to hundreds of µm/s were found. This corresponds to flow rates of around 20 µl/min in a channel with a mm-sized cross section.

		Conclusion Our magnetic artificial cilia can generate a flow of tens of µl/min in microchannels. This is comparable with other microfluidic pumps. Advantages of our approach are that it offers local control, does not require external connections, and is compatible with bio-fluids.

The final project results of the ARTIC consortium have been presented at Microfluidics Conference, Dec. 2010 in Toulouse, during a special session about Cilia-Driven Flows, see url: http://www.microfluidics2010.eu/

Proceedings of ARTIC members are available on this site, see Publications & Presentations

For further information / comments about the project, please contact:
the ARTIC Project Manager:

Prof. dr. ir. J.M.J. den Toonder
Chief Technologist Philips Corporate Technologies
High Tech Campus 7-3.B.007,
5656 AE Eindhoven
The Netherlands
email: ARTIC project manager

For editorial issues : ARTIC office

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