Department of Chemistry, Yanbian University, Park Road 977, Yanji City, Jilin Province 133002, PR China.
Department of Chemistry, Changchun Normal University, Changji North Road 677, Changchun City, Jilin Province 130032, China.
Lab Chip. 2020 Sep 29;20(19):3535-3543. doi: 10.1039/d0lc00620c.
An open-tubular radially cyclical electric field-flow fractionation technique which achieves the online separation of microparticles in a functional annular channel is proposed in this study. The system was set up by using a stainless steel tube and a platinum wire modified with ionic liquid/mesoporous silica materials as the external and internal electrodes. The feasibility for online separation of various particles was experimentally demonstrated. Particles in the channel were affected by a radial electric field and field-flow fractionation (FFF). On the cross section, different particles showed distinctive migration distances depending on their own properties and the different magnitudes of forces being exerted. The same kind of particles form an annular distribution within the same annulus while different particles form annular distributions at varied concentric annuli through electrophoresis. Under a laminar flow of FFF, different sizes of particles formed a conical arrangement within the annular separation channel. With the joint influence of electric field and flow field, different trajectories were obtained and the particles were eventually separated. Voltage, frequency and duty cycle value are the main parameters affecting the separation of particles. By adjusting these parameters, particles migrate in a zigzag trajectory on one side of the electrodes (mode I) and reach both sides of the electrodes (mode II). Six polystyrene particles were completely separated with high resolution within several minutes. Our system offers numerous advantages of label-free, high-resolution and online separation without tedious operations, and it is a promising tool for the effective separation of various micro-objects.
本研究提出了一种在功能环形通道中在线分离微粒的开放式管状径向循环电场流分离技术。该系统由不锈钢管和镀有离子液体/介孔硅材料的铂丝作为外电极和内电极构成。实验证明了在线分离各种粒子的可行性。通道中的粒子受到径向电场和场流分离（FFF）的影响。在横截面上，不同的粒子由于自身性质和所受力的大小不同，表现出不同的迁移距离。同种粒子在同一圆环内形成环形分布，而不同的粒子则通过电泳在不同的同心圆环内形成环形分布。在 FFF 的层流作用下，不同大小的粒子在环形分离通道内形成锥形排列。在电场和流场的共同作用下，获得了不同的轨迹，最终实现了粒子的分离。电压、频率和占空比是影响粒子分离的主要参数。通过调整这些参数，粒子在电极的一侧（模式 I）以之字形轨迹迁移，并到达电极的两侧（模式 II）。在几分钟内，6 个聚苯乙烯粒子完全分离，具有高分辨率。我们的系统具有无标记、高分辨率和在线分离的优势，无需繁琐的操作，是有效分离各种微物体的有前途的工具。
