BioMEMS for Cell Manipulation and Dielectrophoresis

BioMEMS provides precise microscale methods for transporting, trapping, sorting, counting and analyzing biological cells.

Applications in cell manipulation

• Cell trapping and positioning.
• Cell sorting and separation.
• Concentration of rare cells.
• Controlled cell culture environments.
• Cell counting and characterization.
• Isolation of specific cell populations.

Principle of DEP

Dielectrophoresis (DEP) is the motion of a polarizable particle in a non-uniform electric field. A cell becomes polarized when subjected to the electric field. Because the field is non-uniform, the induced electrical forces do not cancel, producing a net DEP force.

In simplified form:
$F_{DEP} \propto r^3 \epsilon_m Re[K(\omega)]
abla |E|^2$

where $r$ is particle radius, $\epsilon_m$ is medium permittivity, $K(\omega)$ is the frequency-dependent Clausius-Mossotti factor, and $E$ is electric-field strength.

• Positive DEP: cells move toward stronger electric-field regions.
• Negative DEP: cells move toward weaker electric-field regions.

By changing frequency, field strength and medium properties, different cell types can be manipulated or separated.