Department of Mechanical Engineering, Jadavpur University, Kolkata 700032, India.
Biomed Microdevices. 2010 Feb;12(1):23-34. doi: 10.1007/s10544-009-9354-0.
Magnetophoretic isolation of biochemical and organic entities in a microfluidic environment is a popular tool for a wide range of bioMEMS applications, including biosensors. An experimental and numerical analysis of magnetophoretic capture of magnetic microspheres in a microfluidic channel under the influence of an external field is investigated. For a given microfluidic geometry, the operating conditions for marginal capture is found to be interrelated in such a manner that a unique critical capture parameter [Pi(crit) = ((Iota(crit)a))(2)/Q(eta)], that is proportional to the ratio of the magnetic force to viscous force, can be identified. Influences of the flow rate, magnetic field and other parameters on the particle trajectories in the microfluidic channel are investigated both numerically and through bright-field imaging under a microscope. Like the event of critical capture, particle trajectories are also found to be guided by a similar parameter, pi. Magnetophoretic capture efficiency of the device is also evaluated as a function of a nondimensional number [Pi(*) = chiP(2)a(2) / (U(null)etah(5)], when both numerical and experimental results are found to agree reasonably well. Results of this investigation can be applied for the selection of the operating parameters and for prediction of device performance of practical microfluidic separators.
在微流环境中通过磁泳分离生化和有机实体是广泛的生物 MEMS 应用（包括生物传感器）的一种流行工具。研究了在外部场影响下，微流道中磁性微球的磁泳捕获的实验和数值分析。对于给定的微流几何形状，发现边缘捕获的操作条件以这样的方式相互关联，即可以识别唯一的临界捕获参数 [Pi(crit) = ((Iota(crit)a))(2)/Q(eta)]，该参数与磁场力与粘性力的比值成正比。通过数值模拟和显微镜下的明场成像，研究了流速、磁场和其他参数对微流道中颗粒轨迹的影响。与临界捕获事件一样，颗粒轨迹也由类似的参数 pi 引导。当数值和实验结果都发现相当吻合时，还评估了器件的磁泳捕获效率作为无量纲数 [Pi(*) = chiP(2)a(2) / (U(null)etah(5))] 的函数。这项研究的结果可用于选择操作参数和预测实际微流分离器的器件性能。
