Dielectrophoretic Characterization and Continuous Separation of Cells in a PDMS Microfluidic Device with Sidewall Conducting PDMS Composite Electrodes - Bioanalysis Advanced Materials Methods and Devices - page 174

Fig. 11.4 ( a ) CM factor versus electric field frequency for yeast and bacterial cells in 2 S/cm DI

m

water and 380 s/cm NaCl solution. The

structural dimensions and dielectric properties of these cells are taken from the literature [ 27 , 29 ].
( b - e ) DEP behaviors of yeast and bacterial cells in stagnant NaCl solution of 380

S/cm NaCl solution and for latex particles in 380

m m

S/cm. ( b ) Well
dispersed yeast cell suspension in the absence of applied AC electric field. ( c ) Cells experience a
repulsive nDEP force after 90 s under 10 V at 10 kHz [ 23 ]. (Reprinted with permission from
Lewpiriyawong et al. (2011).

m

2011 American Chemical Society). ( d ) Cells experience an
attractive pDEP force after 90 s under 10 V at 10 MHz. ( e ) Accumulation of E. coli after 90 s
by an attractive pDEP force under 15.3 V at 1 MHz. These snapshot images were captured with a
20

#

objective

reasonably provide the cross-over frequencies as compared to the predicted ones. The
DEP behaviour of yeast cells was found to change from nDEP to pDEP at ~300 kHz
and from pDEP to no DEP at ~40 MHz. At these applied AC field frequencies, cells
could not move due to the DEP force being zero.