Biological microparticles detection based on differential capacitive sensing and dielectrophoresis manipulation
The manipulation and detection of living cells are essential
requirements for many applications in biology, biotecnology and
medicine. In this study, we propose a microfluidic device, which
facilitated of a differential capacitively coupled contactless
conductively detection (DC4D) coplanar capacitor structure and a
dielectrophoresis (DEP) concentrator based on circular electrodes for
detecting of living cells. With the proposed device, first, the target
and non-Target cells are guided toward the center of the working chamber
due to the dielectrophoresis forces. Then the target cells are captured
by the electrode covered with aptamers, which possess a high affinity
to the target cells. After being flushed to wash away the non-Target
cells in the working chamber, the differential capacitance is read to
identify the presence of target cells. Numerical simulations of the DEP
manipulation and DC4D were performed to proof the concept of the
proposed design. A prototype of the proposed device was fabricated using
micromachining technology. Manipulation and sensing performances of the
device were investigated. The evaluation results show that the
capacitance output changes up to 3fF corresponding to the presence of
about twenty-five cells captured at the electrode.
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