A modular microfluidic platform for cells handling by dielectrophoresis

The physical manipulation of biological cells is of vital importance in the development of miniaturized systems for biological analyses. Dielectrophoresis (DEP) has been reported as a promising method for cell manipulation without physical contact, since it exploits the dielectric properties of cells suspended in a micro-fluidic sample, under the action of high-gradient electric fields. In view of a more extended use of DEP phenomena in lab-on-chip devices, we have worked on a silicon-based platform with microfabricated electrodes, which can offer integrated solutions for a wide variety of applications, customizable for specific user needs. The platform is composed of several functional units, organized in characterization modules for the dielectric analysis and in cell manipulation stages that can be rearranged on a single chip, depending on the target application. It, therefore, represents a complete and innovative research solution, suitable for industrial applications. The non-uniform electric field for cell manipulation is generated by micro-electrodes, patterned on the silicon substrate of micro-fluidic channels, using standard micro-fabrication techniques. Numerical and parametrical modelling using the finite element method was performed to simulate the electric field distribution, quantify the DEP force and, thus, to optimize the geometry of each functional module. In this paper, we report preliminary experimental results obtained by testing some fabricated units using Saccharomyces cerevisiae cells and sheep red blood cells. A system based on the combination of some selected modules is, finally, proposed for sorting cell subpopulations.