Abstract

Dielectrophoresis-Assisted Creation of Cell Aggregates for Lab-On-A Chip Applications

Jonathan Cottet, PostDoc, EPFL

We present a microfluidic platform allowing dielectrophoresis-assisted formation of cell aggregates of controlled size and composition under flow conditions. Cell aggregates are useful intermediary models between the single cell and the tissue to understand how electric properties are modified in a multicellular construct. When specific experimental conditions are met, negative dielectrophoresis (nDEP) allows efficient concentration of cells towards electric field minima and subsequent aggregation. This bottom-up assembly strategy offers several advantages with respect to the targeted application: first, DEP offers precise control of spatial cell organization, which can be adjusted by optimizing electrode design. Then, it could contribute to accelerate the establishment of cell-cell interactions by favoring close contact between neighboring cells. The microfluidic chips were obtained using a novel method of fabrication involving the alignment of a microchannel layer made of PDMS on top of Ti/Pt electrodes. Several parameters have been tested in simulations to find the best configurations for trapping in flow. Those configurations have been tested experimentally with both polystyrene beads and HEK cells. The final design and experimental setup have been optimized to trap cells and release the created aggregates on demand. The aggregate proved to be stable after 5 minutes of cell-cell contact.