Separation Of Micro And Sub-micro Particles Based On Negative Magnetophoresis

Tiny biological particles such as circulating tumor cells and exosomes have shown great potential in cancer diagnosis and pathological assessment.These tiny biological particles have very little content in the sample and are highly dispersed in size,making it difficult to meet the detection concentration requirements,which restricts the development of basic medical research and clinical detection applications.In recent years,the gradually developed and mature microfluidic chip technology provides opportunities for the separation of tiny particles.Due to the advantages of no heat generation,non-contact,easy operation,etc.,the particle manipulation based on the negative magnetophoresis has received more and more attention,but the existing research generally focuses on micro particles,and the control technology of sub-micro particles is still immature.Based on this,this article aims to design a microfluidic chip based on the principle of hydrodynamics and negative magnetophoresis to achieve the separation of micro and sub-micro particles,and combined with numerical simulation and experimental verification to explore the factors and laws affecting the efficiency of particle separation,mainly includes:(1)According to basic theories such as the magnetic fluid flow control equations and the magnetic field distribution characteristics of rectangular permanent magnets,a microfluidic chip based on the sheath flow and negative magnetophoresis is designed.(2)Establish a two-dimensional simulation model to accurately calculate the magnetic field,flow field and particle trajectory,explore the influence of the permanent magnet logarithm,the distance between the magnet and the channel,the inlet velocity ratio,and the inlet velocity on the separation efficiency,and quantify the microchannel The force,speed and migration position of the particles.Adjust relevant parameters to further achieve effective separation of micro and sub-micro particles,sub-micro and sub-micro particles.(3)Conduct microfluidic chip experiments to achieve the successful separation of 3?m particles and 0.8?m particles,and verify the law of particle separation.Analyze the problems in the experiment and propose a further optimization plan designed in this paper.In summary,this paper designs a microfluidic chip for the separation of micro and sub-micro particles.The design of this chip has been verified by numerical simulation and fluorescent particle experiments,and the effective separation of micro and sub-micro particles has been achieved.Influencing factors and laws of particle separation efficiency.The work in this paper can provide a reference for the design and optimization of biological particle separation device based on negative magnetophoresis.