A MEMS-based spiral channel dielectrophoretic chromatography system for cytometry applications

Yilmaz G., Ciftlik A. T., KÜLAH H.

BIOTECHNOLOGY JOURNAL, vol.6, no.2, pp.185-194, 2011 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 6 Issue: 2
  • Publication Date: 2011
  • Doi Number: 10.1002/biot.201000204
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.185-194
  • Middle East Technical University Affiliated: Yes


In this paper design, fabrication, and evaluation of an easy-to-use and low cost dielectrophoretic quantizer are introduced. The device works with standard tools in a biomedical laboratory: a stereo microscope with CCD camera and a voltage supply. A novel spiral microchannel geometry together with the coaxial electrode configuration is established. The device works with a droplet of sample, eliminating microfluidic connections, and external syringes. The proposed geometry decreases the footprint, therefore reduces the device cost, without compromizing the separation and quantization performances. Coaxial electrode geometry enables continuous electric-field application with simple voltage supplies. The devices are fabricated using a simple 3-mask process, and experiments are realized with 1 and 10 mu m polystyrene beads. The results show that 1 mu m particles have an average speed of 4.57 mu m/s with 1.06 mu m/s SD, and 10 mu m particles have an average speed of 544 mu m/s with 105 mu m/s SD. The speed variation coefficient for 1 and 10 mu m beads can be calculated as 23 and 19%, respectively. The size accuracy of the device is +/- 10%, while the resolution is 20%, i.e., particles with radii different from each other by 20% can be separated. Hence, moderate separation performance with minimized cost and standard laboratory equipment is enabled.