Selective trapping of live and dead mammalian cells using insulator-based dielectrophoresis within open-top microstructures.

The manipulation of biological cells is essential to many biomedical applications. Insulator-based dielectrophoresis (iDEP) trapping consists of insulating structures which squeeze the electric field in a conductive solution to create a non-uniform electric field. The iDEP trapping microchip with the open-top microstructures was designed and fabricated in this work. For retaining the merit of microfabrication, the microelectrodes were deposited on the substrate to reduce the voltage required, due to the shortened spacing between them. The dielectrophoretic responses of both live and dead HeLa cells under different frequencies (100 Hz, 1 kHz and 1 MHz) have been investigated herein. The live cells exhibited negative dielectrophoresis at low frequencies of 100 Hz and 1 kHz, but a positive dielectrophoretic response with the frequency at 1 MHz. As for dead cells, positive dielectrophoretic responses were shown at all the frequencies applied. Therefore, selective trapping of dead HeLa cells from live cells was achieved experimentally at the frequency of 1 kHz. The open-top microstructures are suitable for trapping cells or biological samples, and easily proceeding to further treatment for cells, such as culturing or contact detection. The intensity of the emitted light during fluorescent detection will not suffer interference by a cover, as it does not exist herein.