The Mechanism And Experiment Of Micro-nano Particle Concentration By Rotation Induced Charge Electroosmosis

In the biochemical reaction or drug diagnosis process based on the microfluidic technology,the micro-particles such as bacteria or biological cells are rapidly enriched,and the sample volume is reduced to the effective range that the microfluidic device can control is the most basic part of the analysis process.Traditional microfluidic particle collection methods such as dielectrophoresis,alternating electroosmosis,induced charge electroosmosis,etc.are mostly problems such as low collection efficiency,small operating range,and unfavorable for integration.This paper proposes a spin-based induced charge electroosmosis.Efficient particle concentration and directional manipulation method for the purpose of using ROT-ICEO to flexibly regulate the position of particles on the surface of the suspended electrode in the channel,and complete the design of the particle by the particle cantilever pattern formed by continuous contraction to the center.The collection of the position finally achieves the directional movement of the clusters by the regulation of the grid voltage.First,the collection methods of particles in microfluidic chip are reviewed.It is found that the existing collection methods are not ideal and effective for the manipulation of non-charged micro-nano-scale particles on the surface,and then the use of rotation-induced charge electroosmosis for particle manipulation is proposed.The new method.Second,the mechanism of the charge-induced electroosmotic particle aggregation was analyzed.Based on the classical RC circuit theory,the electroosmotic slip velocity on the surface of the suspended electrode under the sinusoidal steady-state signal was deduced;the distribution of the spatial flow field was obtained by numerically solving the flow field in the microchannel.The characteristics,the relationship between the flow stagnation line formed by the reverse vortex above the floating electrode and the particle aggregation phenomenon were clarified,and the electronic control characteristics of the induced charge electroosmosis were studied.Third,it reveals the mechanism of ROT-ICEO’s influence on the particle collection phenomenon: a physical description of the particle motion trajectory in space is presented,the influence of the key electrical parameters of the particles in ROT-ICEO on the flow-induced charge electroosmotic process is analyzed,and the tunable rotation is clarified.The mechanism of inducing AC electroosmosis on the movement of particle clusters explains the reason why the particles on the excitation electrode are collected by adsorption,and the laws governing the orientational movement of the particle clusters by the gate voltage are summarized.Fourth,a microchip was designed and analyzed.The influence of experimental parameters was analyzed.According to the geometric characteristics of the induced electroosmotic flow,a particle-efficient high-efficiency concentration chip for rotation-induced electroosmosis was designed based on the critical dimensions of the experimental device;the key parameters of conductivity and electrode size were studied.The influence of particle collection,the value of the experimental parameters is preferred;the processing technology of the chip is determined and the experimental preparation and the establishment of an experimental platform are performed.Last,efficient particle concentration experiments and particle group orientation migration experiments were conducted: High-efficiency particle concentration experiments confirmed the feasibility of rotationally induced AC charge electroosmosis and the feasibility of improving particle collection efficiency.The experimental results are consistent with the theoretical model;particle beam directional collection The experiments show that the chip’s orientation and manipulation mode of the particles demonstrates that the gate voltage has an effective regulation effect on the directional movement of the clusters.The experimental results verify the effectiveness of the proposed scheme in achieving efficient particle concentration and directional collection.