Versatile microfluidic platform embedded with sidewall three-dimensional electrodes for cell manipulation

The trapping and manipulation of single and small numbers of cells is becoming increasingly important for the development and understanding of cell biology, disease predication and disease diagnostics. In the present work, we developed two dielectrophoresis (DEP) based microfluidic devices, both embedded with three-dimensional (3D) microelectrodes. The first microfluidic device is used for the trajectory switching of cells. The second is a single microfluidic platform used for cell concentration, trapping of single, two cells (doublets) and three cell clusters (triplet). Red blood cell (RBC) trajectory switching to different outlets was achieved by applying 20 Vpp at 1 kHz to the 3D microelectrodes. RBC pre-concentration and trapping was realized by applying 10 Vpp at 5 MHz. During RBC trapping at 5% hematocrit, a trapping efficiency of up to 84% was achieved for doublets and triplets, and at 1% hematocrit, a 67% single cell trapping efficiency was obtained. RBC trajectory switching takes place in ∼2 to 4 s and cell trapping in ∼8 to 10 s following the application of electric field. We performed simulations on comparable 2D planar and 3D microelectrodes which confirmed that 3D microelectrodes support more uniform particle manipulation throughout the channel height direction.