Luo Wenshen, Zheng Chaowen, Sun Cuimin, Li Zekun, You Hui
College of Mechanics, Guangxi University, 100 East University Road, Nanning 530004, China.
School of Mechanical and Electrical Engineering, Beihai Vocational College, 48 Tibet Road, Beihai 536009, China.
Micromachines (Basel). 2025 Mar 29;16(4):404. doi: 10.3390/mi16040404.
The precise preparation and application of nanomicrospheres is currently an emerging research hotspot in the cutting-edge cross-disciplines. As an important functional material, nanosized microspheres show a broad application prospect in biomedicine, chemical engineering, materials science, and other fields. However, microspheres with good monodispersity are still facing technical bottlenecks, such as complicated preparation process and high cost. In this study, a multistage cyclic dielectrophoresis (MC-DEP) technique is innovatively proposed to successfully realize the high-resolution sorting of submicron microspheres. A dielectrophoresis chip adopts a unique electrode design, in which the electrodes are arranged at the top and bottom of the microchannel at the same time. This symmetric electrode structure effectively eliminates the difference in the distribution of dielectrophoretic force in the perpendicular direction and ensures the homogeneity of the initial state of particle sorting. Three pairs of focusing electrodes are in the front section of the microchannel for preaggregation of the microspheres, and the deflection electrodes in the back section are to realize particle size sorting. After this, the upper and lower limits of particle size are limited by multiple cycles of sorting. The multistage cyclic sorting increases the stability of particle deflection under dielectrophoretic forces and reduces the error perturbation caused by the fluid environment. The experimental results show that the multistage cycling sorting scheme significantly improves the monodispersity of the microspheres, and the coefficient of variation of the particle size is significantly reduced from the initial 12.3% to 5.4% after three cycles of sorting, which fully verifies the superior performance of this technology.
纳米微球的精确制备与应用是当前前沿交叉学科中新兴的研究热点。作为一种重要的功能材料，纳米级微球在生物医学、化学工程、材料科学等领域展现出广阔的应用前景。然而，具有良好单分散性的微球仍面临技术瓶颈，如制备工艺复杂、成本高昂。本研究创新性地提出一种多级循环介电泳（MC-DEP）技术，成功实现了亚微米级微球的高分辨率分选。一种介电泳芯片采用独特的电极设计，电极同时布置在微通道的顶部和底部。这种对称电极结构有效消除了介电泳力在垂直方向上分布的差异，确保了粒子分选初始状态的均匀性。三对聚焦电极位于微通道前段用于微球预聚集，后段的偏转电极用于实现粒径分选。在此之后，粒径的上下限通过多次循环分选来限定。多级循环分选提高了粒子在介电泳力作用下偏转的稳定性，减少了流体环境引起的误差扰动。实验结果表明，多级循环分选方案显著提高了微球的单分散性，粒径变异系数从初始的12.3%在三次循环分选后显著降低至5.4%，充分验证了该技术的卓越性能。
