Research On Continuous Cell Separation Biochip Using Dielectrophoresis

Biochip technology has gained more and more attention in recent years because of its real-time analysis, small sample weight, high sensitivity, ease of integration and automation. As one kind of important biochips, the dielectrophoresis (DEP) chip refers to the electrokinetic effect resulting from a polarizable particle under the action of a non-uniform electric field and achieves to manipulate, transport and separate different bio-particles. DEP chip has acquired wide application in life science domain and analytical chemistry domain since it offers many advantages, including non-invasive detection, high sensitivity and fast speed.This work is supported by the High Technology Research and Development Program of China. The DEP chip is planned to be used for sample preparation which needs the chip offer fast speed, ease of automation and miniaturization.First, DEP mechanisation is researched, and the expression of DEP force is derived based on dipole moment mechanisation. The frequency spectrums are analysed for polystyrene sphere and yeast cell and the muti-frequency DEP mechanisation is also studied which deduces the principle for cell separation based on multi-frequency DEP.The main structure of the DEP chip is designed and simulation analysed based on the result. The dispositions of the potential, electric field and DEP force are studied. The shape of the access channel wall is optimized to further improve the separation efficiency. The possibility that using planar electrodes take the place of 3-D electrodes under certain condition is discussed. The structure is finally decided based on the simulation analysis, and the dispositions of the electhermal flow, thermal field, and DEP force is analysed to make sure that the DEP chip can accomplish the functions by plannedBased on system structure and function, PDMS is choiced as the material of micro-channel for DEP chip. SU-8 is fabricated as the mould for PDMS channel by photolithography, and the PDMS channel is processed using rapid prototyping technology. ITO glass is choiced as the material of the substrate and ITO is etched to the array which we need. The PDMS channel and the substrate are bonded together using oxygen ion bonding technology.Experiment research is proceeded using DEP chip. The research for focusing and shifting polystyrene spheres is carried through and the effect of the potential to the results is also studied. The cell separation project proposed in this article is proved by the experiment research of separating polystyrene spheres and yeast cells.