Feng Haoqiang, Shen Shitao, Jin Mingliang, Zhang Qilin, Liu Mengjun, Wu Zihao, Chen Jiamei, Yi Zichuan, Zhou Guofu, Shui Lingling
International Joint Laboratory of Optofluidic Technology and System, National Centre for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics & School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510006, P. R. China.
Shenzhen Bao'an District Traditional Chinese Medicine Hospital, Shenzhen, 518133, P. R. China.
Small. 2023 Nov;19(45):e2302998. doi: 10.1002/smll.202302998. Epub 2023 Jul 14.
Droplet array is widely applied in single cell analysis, drug screening, protein crystallization, etc. This work proposes and validates a method for rapid formation of uniform droplet array based on microwell confined droplets electro-coalescence of screen-printed emulsion droplets, namely electro-coalescence droplet array (ECDA). The electro-coalescence of droplets is according to the polarization induced electrostatic and dielectrophoretic forces, and the dielectrowetting effect. The photolithographically fabricated microwells are highly regular and reproducible, ensuring identical volume and physical confinement to achieve uniform droplet array, and meanwhile the microwell isolation protects the paired water droplets from further fusion and broadens its feasibility to different fluidic systems. Under optimized conditions, a droplet array with an average diameter of 85 µm and a throughput of 10 in a 10 cm × 10 cm chip can be achieved within 5 s at 120 Vpp and 50 kHz. This ECDA chip is validated for various microwell geometries and functional materials. The optimized ECDA are successfully applied for digital viable bacteria counting, showing comparable results to the plate culture counting. Such an ECDA chip, as a digitizable and high-throughput platform, presents excellent potential for high-throughput screening, analysis, absolute quantification, etc.
液滴阵列广泛应用于单细胞分析、药物筛选、蛋白质结晶等领域。本工作提出并验证了一种基于微阱限制的丝网印刷乳液液滴电聚结快速形成均匀液滴阵列的方法，即电聚结液滴阵列（ECDA）。液滴的电聚结是根据极化诱导的静电和介电泳力以及介电润湿效应实现的。光刻制造的微阱高度规则且可重复，确保相同的体积和物理限制以实现均匀的液滴阵列，同时微阱隔离可保护成对的水滴免于进一步融合，并拓宽了其对不同流体系统的适用性。在优化条件下，在120 Vpp和50 kHz的电压下，可在5 s内在10 cm×10 cm的芯片中实现平均直径为85 µm且通量为10的液滴阵列。该ECDA芯片已针对各种微阱几何形状和功能材料进行了验证。优化后的ECDA成功应用于数字活菌计数，结果与平板培养计数相当。这种ECDA芯片作为一种可数字化的高通量平台，在高通量筛选、分析、绝对定量等方面具有巨大潜力。
