Construction Of An Orthogonal Electrophoresis Separation System And Its Application In Particulate Matter Applications In Separation

The separation and screening of micro-objects（nanoparticles,proteins,exosomes,single cells,etc.）is a key scientific issue in the fields of biomedicine,materials science,and precision medicine.For applications,a rapid,high-throughput,continuous,and precise separation and screening platform is urgently needed.Separation methods using the characteristics of material flow at the micro-nano scale include inertial migration separation,squeeze flow,hydrodynamic filtration,and deterministic displacement separation.Although these methods have the advantages of continuous,rapid and high-throughput,the manipulation and separation of microfluidics make them highly effective.high challenge.The continuous separation strategy based on active field assistance（such as magnetic field,acoustic field,light and electric field assistance,etc.）makes it feasible for flexible manipulation of matter at the micro-nano scale.However,these continuous separation methods still have the problems of single separation channel,single target size,low separation efficiency and low throughput and difficulty in enrichment.In conclusion,it may be an effective solution to integrate the real-time regulation of the active field and the fast and high-throughput characteristics of the flow field on the microfluidic chip platform.Therefore,based on the above technical defects and requirements,it is urgent to develop an active field-assisted multi-channel continuous separation and enrichment method suitable for multi-scale targets.In this paper,a continuous separation method of electric field-assisted flow field integrating focusing,separation and enrichment,namely orthogonal chip electrophoresis separation method,is proposed.In this method,the target substance driven by the fluid is squeezed by the laminar flow of the mobile phase in the orthogonal direction in the system to achieve linear focusing,and is driven by the deflection electric field to migrate to the separation channel,thereby realizing separation and enrichment.The specific research contents and results are as follows:（1）Establish the separation theory of orthogonal electrophoresis separation system.The separation and focusing theory of the system was studied,and the effects of the properties of the applied electric field,fluid flow rate,and target material charge ratio on the deflection and separation behavior in the separation system were explored based on three relationships.Feasibility of collecting micro-and nano-scale substances.（2）Set up an orthogonal electrophoresis separation system.The system includes sampling system,separation system,power supply system and monitoring system.A microfluidic chip electrophoresis system with different functionalities and multi-dimensional orthogonality was designed and prepared.Among them,the separation system is the core part of the technology.The sheath liquid focusing injection device module that uses the flow field to realize micro-nano-scale substances is designed,and the problems of air bubbles and atmospheric pressure existing in traditional electrophoresis technology are solved by exploring the electrode position and device opening and closing.Interference from subsequent separations.（3）To explore the focusing,deflection and separation behavior of small molecules and particles in the orthogonal chip electrophoresis separation system.Through the controllable manipulation of the flow field,the optimal flow rate ratio of the sheath liquid focusing of the target object is determined,and the linear relationship tanθ∝μ_eand tanθ∝E between the deflection angle of the target object,the electric field strength and the electric mobility are determined by adjusting the electric field parameters.To explore the separation performance,recovery and throughput of 5μm blue and green polystyrene particles of the same size by the orthogonal electrophoresis system,it has good performance for 5μm blue and green polystyrene particles at E=25-35 Vcm^-1Separation performance,the highest recovery rate is 85%,and the throughput is 0.5 m L min^-1;the orthogonal electrophoresis system has good separation performance for 3μm and 5μm polystyrene particles of different sizes at E=25-30 Vcm^-1,and the throughput The amount is 0.5 m Lmin^-1.（4）Online separation of micro-and nano-scale substances such as proteins.Based on the orthogonal electrophoresis system,we tried to separate and enrich proteins,and successfully realized the online and continuous separation of protein HSA enzyme and FITC,which provided a new method and new platform for the subsequent continuous separation and screening of complex proteins.The orthogonal electrophoresis separation system proposed in this paper is expected to realize online,continuous,high-throughput separation and enrichment of different micro-and nano-scale substances.Based on the previous innovation foundation,a multi-dimensional orthogonal chip electrophoresis system can be established,and the directional migration of particles can be regulated by multi-electric fields,which has great feasibility for online separation and enrichment of targets.The research and development of cell mass spectrometry,etc.has creative application prospects.