Performance assessment of micromixers for bio-fluidic processing with magnetic beads
Performance assessment of micromixers for bio-fluidic processing with magnetic beads
复制标题
用于磁珠生物流体处理的微混合器的性能评估
DOI：
10.1109/jmems.2004.835775
复制
发表时间：
2006
影响因子：
2.7
通讯作者：
C. Chainarong
中科院分区：
文献类型：
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作者：
C. Chainarong
设计、制造并测试了一种结构简单、高效的磁力驱动混合器。它被设计为促进磁珠和生物分子在微通道中的混合，其中混合由于其低雷诺数而非常低效。通过适当的力场时间变化，实现混沌混合，从而使混合变得有效。混合装置由作为磁场源的嵌入式微导体和引导工作流体流的微通道组成。它表明，一对集成的微导体提供了一个局部磁场足够强，以吸引附近的磁珠。磁珠的混合是通过在低至10/sup-2/的雷诺数下向一排导体施加随时间变化的控制信号来实现的。已经进行了二维数值模拟，以设计的通道和电极的配置，创建珠的混沌运动。结果发现，一个简单的二维蛇形通道的几何形状与横向电极是能够创建的拉伸和折叠的材料线，这是混沌的表现。模拟预测的混合模式已被证实的流动可视化和PTV（粒子跟踪测速仪）在混沌混合器制造，这将大大增加附着到目标生物分子的珠。应用控制信号的最佳频率搜索通过评估数值和实验粒子跟踪的李雅普诺夫指数。发现最佳Strouhal数的范围是5<St<12，这是由通道宽度和平均速度定义的。
An efficient magnetic force driven mixer with simple configuration is designed, fabricated, and tested. It is designed to facilitate the mixing of magnetic beads and biomolecules in a microchannel, where mixing is unavoidably inefficient due to its low Reynolds number. With appropriate temporal variations of the force field, chaotic mixing is achieved, hence the mixing becomes effective. The mixing device consists of embedded microconductors as a magnetic field source and a microchannel that guides the streams of working fluid. It is demonstrated that a pair of integrated micro conductors provides a local magnetic field strong enough to attract nearby magnetic beads. Mixing of magnetic beads is accomplished by applying a time-dependent control signal to a row of conductors, at the Reynolds number of as low as 10/sup -2/. Two-dimensional numerical simulation has been performed to design the configuration of the channel and electrodes, which creates chaotic motion of beads. It is found that a simple two-dimensional serpentine channel geometry with the transverse electrodes is able to create the stretching and folding of material lines, which is a manifestation of chaos. The mixing pattern predicted by the simulation has been confirmed by both flow visualization and PTV (particle tracking velocimetry) in the chaotic mixer fabricated, which should greatly increase the attachment of beads onto the target biomolecules. The optimum frequency of applied control signal is searched by evaluating the Lyapunov exponent in both numerical and experimental particle tracking. It is found that the range of optimum Strouhal number is 5<St<12, which is defined by the channel width and the mean velocity.