Microparticles Enrichment And Separation By AC Dielectrophoresis Chip Based On Printed Circuit Board Technology

Dielectrophoresis(DEP) is one of the important technology for particles’ enrichment and separation in microfluidic system. Compared with mechanical or optical approaches, it has remarkable advantages such as simple process, easy operation, fast response and easy to realize miniaturization and automation. It is great potential to be used in accurately capture, enrichment, separation and transport of some large particles and biological cells. Most of DEP chips in existence fabricated by Micro-Electro-Mechanical System(MEMS), which still can’t realize mass-production at present, limiting the popularization and application of the chip. However, it is worth to notice that Printed circuit board(PCB) process has prominent advantages in packaging and cost-effective mass-production. Therefore, it is of great significance and practical utility to fabricate DEP chip by PCB process and realize particulate manipulation.On account of the limitation of PCB process resolution, the optimization design of AC DEP chip based on PCB process and the theory and experiment of realizing particles’ enrichment and separation are studied in this paper. It includes the following several aspects specifically.①The theory of particles’ enrichment and separation manipulated by dielectrophoresis are analyzed. Force analysis is made for neutral particles suspending in electrolyte solution with non-uniform electric field, obtaining the mainly influencing factors of particle movement manipulated by DEP force.②Two-dimensional model of interdigitated DEP chip is built to simulate the distribution of electric field. In view of the resolution of PCB process, the magnitude and direction of DEP force suffered by particles suspending in chip are analyzed further, getting the relationship between DEP force with Channel height, electrode characteristic parameters(electrode width/spacing) and voltage amplitude and optimizing the electrode parameters of DEP chip.③Ignoring the electrode thickness, Laplace equation and Fourier series analysis method is used to derive the expression of particle levitation height which is the key parameter affecting the dielectrophoresis separation, verified by numerical simulation. In addition, the influence of electrode thickness on particle levitation height decreases with the electrode thickness decreasing.④Preparation of interdigitated DEP chip based on PCB processing, the electrode width/gap is 100 microns, setting up the experimental system. With polystyrene microspheres and yeast cells as the samples, the experiment of particle manipulation by dielectrophoresis is completed. The enrichment effect is evaluated through the image counting method.The results show that polystyrene microspheres suffer negative dielectrophoresis(n DEP) in 100 k Hz~10MHz, assembling in electrode center, electrode gap center or a plane with certain height. The number of polystyrene microspheres after enrichment is three times as much before enrichment. However, yeast cells suffer positive dielectrophoresis(p DEP) at 100 k Hz~10MHz, assembling in electrode edge, and the number of yeast cells after enrichment is two times as much before enrichment. Combining with field flow separation technology, it is realized to the separation of two kinds of samples in three-dimensional space.