The University of Southampton

Dielectrophoretic Separation of Particles

(a) A mixture of particles at the inlet. (b) Separation of 1 and 2 um particles in the middle of the electrode arrays. 2um deflected. (c) Separation of 1 and 2um particles at the exit of the electrode arrays. (d) Still video image of separation.
Microfluidics and Lab-on-a-chip
Ministry of Higher Education, Malaysia, University of Putra Malaysia (UPM) and Royal Academy of Engineering

A novel separation device uses dielectrophoresis to achieve 100% non-contact separation of a mixture of particles. The method is continuous and flow through, involves no fouling and ensuring longevity of operation. It is sensitive to medium conductivity, applied frequency and voltage. This project will present a characterisation of a microfluidic device using an incorporating angled microelectrode arrays for the continuous dielectrophoretic separation of particles. The characterisation is essential to get specific indication for each particle type deflects, behaves and hence separated at the end of the arrays. A new optimised device design consists of sequential interdigitated electrode arrays with angle of 60 degree is introduced. This device uses negative dielectrophoresis to achieve gradual deflection through the sequential influence of the electrodes in the array. A microfluidic channel is made using two layers of dry film resist SY320 with its thickness reduces to approximately 30µm height, which then could increase the dielectrophoretic force. The data is examined by measuring deflection of particle from the side wall against frequency at different voltage applied. When a mixture of particles of 2µm and 1µm are in the channel, they can then physically be separated along the arrays achieving 100% spatial separation at the outlet of the channel simply by means of a channel junction with as low as operating voltage of 10V. The project will discuss results obtained and the optimisation of separation that is achievable by choice of frequency and voltage.

Primary investigators

Associated research group

  • Nano Research Group
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