It was previously reported in the Velev group that, 1D chains and 2D arrays can be successfully formed in AC electric fields on electrically controlled chips by dielectrophoresis. These assembled cell chains were made permanent by adding functionalized particles to the cell suspension. Further, it has also been reported that IgG-functionalized latex particles agglutinated with an antigen exhibits a distinguishable impedance spectroscopy response. (See Shalini Gupta’s page) The focus of my research is to characterize the assembly and interactions of cells and synthetic particles in AC electric fields using impedance spectroscopy for potential use in new advanced materials, biosensors, and microdevices.

In my current research, I am investigating the effects of changing media environment parameters on the impedance spectroscopy of yeast / latex particle and yeast / gold nanoparticle solutions. The yeast / particle solutions are injected into a 150 micron chamber over interdigitated electrodes of varying gap widths. The gold interdigitated electrode chips are made on glass substrates using negative resist photolithography techniques. The impedance and phase angle of the AC field at varying frequencies (from 1Hz to 1MHz) through the chamber is measured. Preliminary results show the agglutination of yeast and particles has a distinct effect on the impedance spectroscopy.

As my research continues, I plan to examine the effects of changing the interdigitated electrode gap geometry on the repeatability of the impedance spectroscopy measurements. The application will then be extended to study the impedance spectroscopy at higher frequencies (above 1MHz), the effect of using functionalized particles in suspension with yeast cells, and mammalian cell / particle suspensions.