Figure 2

Microscopic images of Listeria monocytogenes exhibiting negative and positive DEP at the interdigitated microelectrode. (a)Listeria monocytogenes cells exhibit negative DEP at 1 kHz and 3 Vpp; they are collected at the centers of the finger electrodes. (b) Some of the cells exhibit negative DEP, while others exhibit positive DEP, at 10 kHz and 3 Vpp; Cells are collected at both the centers of the finger electrodes and the edges of the finger electrodes. (c) As frequency increases to 50 kHz (at 3 Vpp), all the cells exhibit positive DEP and are collected at the edges of the finger electrodes.