【摘要】 在微流控芯片中,利用磁场力操控技术实现磁珠的有效捕获在生物检测和生化分离等方面应用广泛,其在微尺度下的运动特性与磁场力和黏滞阻力的关系显得尤为重要。根据磁珠在微通道中的受力和运动方程,建立磁场和流场共同作用下磁珠的二维动力学数值模型,对三种磁场分布下磁珠的运动特性以及不同入口速度和磁场强度对磁珠捕获率的影响进行数值仿真。研究表明:磁体高宽比(h/w)越大,磁体内部的磁通密度越大且分布越均匀。当磁体高宽比从0. 5增至6时,极性相同磁体的捕获率范围为26. 7%～100%;极性相反和单磁体的磁珠捕获率最大值分别为63. 3%和53. 3%。双磁体的磁化方向对捕获率的影响为:h/w <2时,极性相反的磁珠捕获率较大;反之则小于极性相同的捕获率。通过仿真计算,入口流速介于1 mm/s～2 cm/s时,磁珠捕获率随流速的增加而减小。结果可用于实验指导流体流速进而优化磁珠使用量;并对微流控芯片的设计具有理论指导意义。更多还原

【Abstract】 In microfluidic chips,magnetic force manipulation technology can achieve the effective capture of magnetic beads,which has been widely used in biological detection and biochemical separation. The magnetic force and viscous resistance have an important effect on the dynamic characteristics of magnetic beads on the microscale.According to force and motion equation of magnetic beads in microchannel,the two-dimensional dynamic numerical model of magnetic beads was established under the interaction of magnetic field and flow field. Not only motion characteristics of magnetic beads under three magnetic fields also capture ratio with different inlet velocity and magnetic field strength was numerically simulated. The results show that magnetic flux density and uniformity inside magnets are proportional to aspect ratio( h/w) of magnets. When the aspect ratio of magnets is increased from 0. 5 to 6,the capture rate of magnets with the same polarity ranges from 26. 7% to 100%; The maximum capture rate about magnetic beads of opposite polarity magnets and single magnet are 63. 3% and 53. 3%,respectively. Effect of magnetization direction of double magnets on the capture rate is when aspect ratio h/w is less than 2,capture rate of magnetic beads with opposite polarities is higher,which will less than the same polarity magnetic capture rate contrarily. When inlet flow rate is between 1 mm/s and 2 cm/s,magnetic beads capture rate decreases with increasing of velocity by simulation calculation. These results can be used to guide the fluid speed and optimize magnetic beads usage in the experiment,and have theoretical guiding significance for design of the microfluidic chips.更多还原