Integrated Techniques Of Free Flow Electrophresis Chip

Microfluidic chip has been widely developed and been in important applications in the past ten years, micro total analysis system has integrated these traditional separation steps into a single chip. Free flow electrophoresis play an important role in microfluidic field, is an effective separation and enrichment detection technology. However, the applied voltage of traditional free-flow electrophoresis is high, due to the interference of the bubble, causing not continuous separation and other issues. In addition, free-flow electrophoresis is seldom integrated as capillary electrophoresis. Electrodes, micro pump integrated in the free-flow electrophoresis can reduce the volume of free-flow electrophoresis with important significance. To solve these problems, we use PMMA and polyimide gel as a material, with the use of micro engraving machine to fabricate a free flow electrophoresis with an integrated micro pump. The fabrication process is simple and has a very low cost during production.Firstly, the basic theory of free-flow electrophoresis was reviewed, including band broadening theory and PHASEGUIDE theory, PHASEGUIDE theory has important significance for getting rid of bubbles. COMSOL with laminar flow, electrostatic, particle tracking module has been used for simulation of FFE in the electric field and flow field. The true quality of lead ions and charge number was applied during simulation. Furthermore the hydrodynamic focusing was simulated, the simulation results showed the sample exports due to the effects of the flow rate of the buffer.We designed and produced a valveless micropump using PMMA material with AutoCAD and Altium Designer software. Finally VIP3530was for production. The product of micropump was tested for flow rate and back pressure. Test shows micropump with good performance, the micropump is feasible to integrate with FFE. Under±110V of square wave, the flow rate increase with frequency then decrease with frequency, the flow rate reach culminate at500Hz, the flow rate is600μL/min.The use of PMMA and polyimide two polymers is used for fabrication integrated free flow electrophoresis. Basis of prior experimental data, we integrated electrode bubble expelling structure and micro-pump free flow electrophoresis. The geometric dimensioningis40mm long,20mm wide, with the weight of electrode chamber1mm.And hydrodynamic focusing experiments was designed to investigate the effect of buffer flow rate for sample separation. The fluid shape and ohmic characteristic curve was analysed for the flow free flow electrophoresis. Micro-PIV for free flow electrophoresis separation were tested.Finally, the free-flow electrophoresis was tested by electrochemical detection methods, including differential pulse voltammetry. Designing the experiments, ionmeter and ion selectiveelectrode were used to test the performance of free-flow electrophoresis. Results show electrochemical detection was fit for detection of free-flow electrophoresis enrichment of lead ions. The enrichment efficiency index reached3, integrated FFE worked well, and with a great of meaning for microfluidic device.