1. Micro-moulded magnetic artificial cilia for anti-fouling surfaces
Shuaizhong Zhang1,2, Ye Wang1 and Jaap den Toonder1
1Eindhoven University of Technology, the Netherlands
2China Scholarship Council, the People’s Republic of China
The (bio-)fouling of surfaces submerged in liquid forms a serious problem for many applications. One inspiration to address this issue is the use of cilia which are oscillating micro-hairs found in nature, and which are very effective in particle manipulation. Micro-moulding is one of the best controllable and cost-effective ways to fabricate engineered analogues of cilia, magnetically actuated artificial cilia (MAAC). Thus we aim to mould MAAC to create surfaces for particle manipulation and anti-fouling.
Motivation and Aim
Experiments
Micro-moulding Process of MAAC
Step 1:
Standard photo-lithography to make SU-8 moulds
Step 2:
Fill with a PDMS / carbonyl-Iron powder (CIP) mixture
Step 3:
Remove top layer
Step 4:
Apply uniform magnetic field to align CIP
PDMS and CIP mixture
Step 5:
Pour pure PDMS, and cure the mixture
PDMS
Step 6:
Peel off MAAC
MAAC
Transparent PDMS base
wafer
SU-8
UV light
Results
We have moulded MAAC with diameters of 50 and 100 μm with lengths 400 and 600 μm respectively (Fig. 1a,1b). The moulded MAAC can generate fluid flow with speed up to 208 μm/s (Fig. 2) when integrated in circular microfluidic chips and actuated with a home-built magnet setup. We also moulded MAAC with CIP constrained in the cilia tips using gravity-induced sedimentation (Fig. 1c), however these Iron-tipped cilia could be actuated only slightly using our magnetic setup since it lacks a large magnetic field gradient.
Mask
Fig. 1: MAAC with (a) diameter 50 μm with length 400 μm; (b) diameter 100 μm with length of 600 μm; (c) Iron-tipped cilia.
Fig. 2: Typical water flow velocities generated by our moulded MAAC when actuated at different frequencies.
Conclusion
MAAC with high aspect ratio have been moulded. These MAAC can be employed to generate fluid flow in microfluidic devices. Further work is to explore the particle manipulation capacity of the moulded MAAC.
REFERENCES
1. Toonder, J.M.J. den and Onck, P.R. (eds) (2013), Artificial Cilia, Cambridge: RSC Publishing; ISBN:
2. Anna C. Balazs, Amitabh Bhattacharya, Anurag Tripathi, and Henry Shum, Designing Bioinspired Artificial Cilia to Regulate Particle−Surface Interactions, J. Phys. Chem. Lett, 5, (2014).
/ Microsystems Group / Department of Mechanical Engineering / Eindhoven University of Technology