11
Gold Electrode
AC Field with Alternative on/o Control
Cell S
Buer Solution
Lower Outlet Upper Outlet
Insulating Posts
4.15 mm
1 mm
9.40 mm
4
3
10.16 mm
0.34 mm
O On OnO O On O On O On O
Figure 1.7: DEP microuidic chip for cell sorting: (a) parallel electrode DEP cell sorting chip [97]
(used with permission from the Royal Society of Chemistry; and (b) insulating DEP cell enrichment
chip [100] (used with permission from AIP Publishing).
e strength and direction of DEP force and torque are related to the cell, solution, and
electrical signal parameters. By adjusting electrical signal parameters, precise manipulation of single
cells and cell population can be achieved. As MEMS technologies advance, the electrodes in micro-
uidic chips can be made more sophisticated, extending from 2D planar electrodes to thick-elec-
trode structures. And the microuidic chip based on the DEP technology can be easily combined
with other various technologies to realize multifunctional operations.
e above sample manipulation mechanisms are summarized in Table 1.1.
Table 1.1: Biological control mechanisms in microuidic chips
Methods eory rougput Application
Fluidic Microstructures or microvalves in microchannels
are used to control microuidics to control the
biological control
High Cell capture,
separation
Optical e optical gradient well formed by a single
beam is used to capture and move single cells
Low Cell capture,
Translation, Sorting
Magnetic Cell surface antigens are combined with specic an-
tibodies attached to magnetic beads to manipulate
cells using an external magnetic eld
High Cell enrichment
Acoustic e micro-operation of cells is realized by the
acoustic eld formed in the microchannel by
piezoelectric transducer device
High Cell separation,
cell trap
DEP e polarization of cells are formed electric di-
pole under non-uniform electric eld, which is
subjected to DEP force or torque
High Sorting,Separation,
Electro-rotation
1.2 SAMPLE MANIPULATION METHODS IN MICROFLUIDIC CHIPS