Lewpiriyawong Nuttawut, Xu Guolin, Yang Chun
School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
Institute of Bioengineering and Nanotechnology, Singapore.
Electrophoresis. 2018 Mar;39(5-6):878-886. doi: 10.1002/elps.201700395. Epub 2018 Jan 22.
This paper presents the use of DC-biased AC electric field for enhancing cell trapping throughput in an insulator-based dielectrophoretic (iDEP) fluidic device with densely packed silica beads. Cell suspension is carried through the iDEP device by a pressure-driven flow. Under an applied DC-biased AC electric field, DEP trapping force is produced as a result of non-uniform electric field induced by the gap of electrically insulating silica beads packed between two mesh electrodes that allow both fluid and cells to pass through. While the AC component is mainly to control the magnitude of DEP trapping force, the DC component generates local electroosmotic (EO) flow in the cavity between the beads and the EO flow can be set to move along or against the main pressure-driven flow. Our experimental and simulation results show that desirable trapping is achieved when the EO flow direction is along (not against) the main flow direction. Using our proposed DC-biased AC field, the device can enhance the trapping throughput (in terms of the flowrate of cell suspension) up to five times while yielding almost the same cell capture rates as compared to the pure AC field case. Additionally, the device was demonstrated to selectively trap dead yeast cells from a mixture of flowing live and dead yeast cells.
本文介绍了在装有密集填充硅胶珠的基于绝缘体的介电泳（iDEP）流体装置中，使用直流偏置交流电场来提高细胞捕获通量。细胞悬浮液通过压力驱动流被输送通过iDEP装置。在施加的直流偏置交流电场下，由于填充在两个允许流体和细胞通过的网状电极之间的电绝缘硅胶珠的间隙所感应的非均匀电场，产生了介电泳捕获力。虽然交流分量主要用于控制介电泳捕获力的大小，但直流分量会在珠子之间的腔体内产生局部电渗（EO）流，并且可以将EO流设置为沿主压力驱动流方向移动或与之相反。我们的实验和模拟结果表明，当EO流方向沿（而非逆）主流动方向时，可实现理想的捕获。使用我们提出的直流偏置交流场，该装置可以将捕获通量（以细胞悬浮液的流速计）提高至五倍，同时与纯交流场情况相比，产生几乎相同的细胞捕获率。此外，该装置被证明能够从流动的活酵母细胞和死酵母细胞的混合物中选择性地捕获死酵母细胞。
