Misra I, Kumaran V
Chemical Engineering Department, Indian Institute of Science, Bengaluru, India.
Biomicrofluidics. 2024 Aug 23;18(4):041501. doi: 10.1063/5.0211204. eCollection 2024 Jul.
Microfluidic systems have enormous potential for enabling point-of-care diagnostics due to a number of advantages, such as low sample volumes, small footprint, low energy requirements, uncomplicated setup, high surface-to-volume ratios, cost-effectiveness, etc. However, fluid mixing operations are constrained by molecular diffusion since the flow is usually in the laminar regime. The slow nature of molecular diffusion is a technological barrier to implementing fluid transformations in a reasonable time. In this context, magnetically actuated micro-mixers of different sizes, shapes, materials, and actuation techniques provide a way to enhance fluid mixing in microfluidic devices. In this paper, we review the currently existing micro-mixing technologies. From a fundamental perspective, the different magnetization models for permanent and induced dipoles are discussed. The single-particle dynamics in steady and oscillating magnetic fields is studied in order to determine the flow generated and the torque exerted on the fluid due to the magnetic particles. The effect of particle interactions, both magnetic and hydrodynamic, is examined.
由于诸多优点，如样本量小、占地面积小、能量需求低、设置简单、表面积与体积比高、成本效益高等，微流控系统在即时诊断方面具有巨大潜力。然而，由于流动通常处于层流状态，流体混合操作受到分子扩散的限制。分子扩散的缓慢特性是在合理时间内实现流体转变的技术障碍。在此背景下，不同尺寸、形状、材料和驱动技术的磁驱动微混合器为增强微流控设备中的流体混合提供了一种方法。在本文中，我们回顾了当前现有的微混合技术。从基本角度出发，讨论了永久偶极子和感应偶极子的不同磁化模型。研究了稳定和振荡磁场中的单粒子动力学，以确定由于磁性粒子产生的流动以及施加在流体上的扭矩。研究了粒子间磁性和流体动力学相互作用的影响。
