Cell trapping and detection by dielectrophoresis with SU-8 grooves

Abstract

In this paper, a novel dielectrophoretic microfluidic device is proposed for cell trapping and detection. The dielectrophoresis device consists of inter-digital electrodes and SU-8 grooves. The SU-8 structure with grooves was fabricated on the top of the electrodes with the strongest electric field formed at the edges of the exposed electrodes. Cells can be trapped in the SU-8 grooves by positive dielectrophoretic force and released back to the fluid flow by negative dielectrophoretic force. The height of the grooves is designed such that the cells remained trapped and cannot be flushed away by the fluid flow when the electric field is turned off. This allows further cell analysis to be conducted in a saline buffer with the electric field turned off, avoiding the electrodes from getting burned in a high conductivity medium. The trapping and detection process is demonstrated using human colon cancer cells (HT-29 cells) and cryptosporidium parvum. Viability test in a phosphate buffer was conducted after HT-29 cells are trapped by the grooves. The capture of cryptosporidium parvum oocyst cells in water followed by cell specific detection by anti-cryptosporidium antibody is also reported. © 2013 Springer-Verlag.