Use of high frequency electrorotation to identify cytoplasmic changes in cells non-disruptively.

In this paper we demonstrate how the use of frequencies ranging from 50 kHz to 5 GHz in the analysis of cells by electrorotation can open the path to the identification of differences not detectable by conventional set-ups. Earlier works usually reported electrorotation devices operating below 20 MHz, limiting the response obtained to properties associated with the cell membrane. Those devices are thus unable to resolve the physiological properties in the cytoplasm.

Efficient AC electrothermal flow (ACET) on-chip for enhanced immunoassays.

Biochemical reaction rates in microfluidic systems are known to be limited by the diffusional transport of reagents, leading often to lowered sensitivity and/or longer detection times in immunoassays. Several methods, including electrically powering electrodes to generate AC electrothermal flow (ACET) on-chip, have been adopted to enhance the mass transport of the reagents and improve microfluidic mixing. Here, we report a novel ACET electrode design concept for generating in-plane microfluidic mixing vortices that act over a large volume close to the reaction surface of interest.

Planar hydrodynamic traps and buried channels for bead and cell trapping and releasing.

We present a novel concept for the controlled trapping and releasing of beads and cells in a PDMS microfluidic channel without obstacles present around the particle or in the channel. The trapping principle relies on a two-level microfluidic configuration: a top main PDMS channel interconnected to a buried glass microchannel using round vias. As the fluidic resistances rule the way the liquid flows inside the channels, particles located in the streamlines passing inside the buried level are immobilized by the round with a smaller diameter, leaving the object motionless in the upper PDMS channel.