Kim Jaewook, Kim Taeyung, Ji Inseo, Hong Jiwoo
School of Mechanical Engineering, Soongsil University, 369 Sangdo-Ro, Dongjak-Gu, Seoul 06978, Korea.
Micromachines (Basel). 2022 Apr 10;13(4):593. doi: 10.3390/mi13040593.
Contact charge electrophoresis (CCEP) is an electrically controllable manipulation technique of conductive droplets and particles by charging and discharging when in contact with the electrode. Given its straightforward operation mechanism, low cost, and ease of system construction, it has gained traction as a versatile and potential strategy for the realistic establishment of lab-on-a-chip (LOC) in various engineering applications. We present a CCEP-based digital microfluidics (DMF) platform with two parallel electrode modules comprising assembled conventional pin header sockets, allowing for efficient mixing through horizontal and vertical shaking via droplet reciprocating motions. The temporal chromic change caused by the chemical reaction between the pH indicator and base solutions within the shaking droplets is quantitatively analyzed under various CCEP actuation conditions to evaluate the mixing performance in shaking droplets by vertical and horizontal reciprocating motions on the DMF platform. Furthermore, mixing flow patterns within shaking droplets are successfully visualized by a high-speed camera system. The suggested techniques can mix samples and reagents rapidly and efficiently in droplet-based microreactors for DMF applications, such as biochemical analysis and medical diagnostics.
接触电荷电泳（CCEP）是一种通过与电极接触时充电和放电来对导电液滴和颗粒进行电可控操纵的技术。鉴于其操作机制简单、成本低且易于构建系统，它已成为一种通用且有潜力的策略，可用于在各种工程应用中切实建立片上实验室（LOC）。我们展示了一个基于CCEP的数字微流控（DMF）平台，该平台具有两个平行电极模块，由组装好的传统针座插座组成，通过液滴的往复运动实现水平和垂直摇晃，从而实现高效混合。在各种CCEP驱动条件下，对摇晃液滴内pH指示剂与碱溶液之间化学反应引起的时间色度变化进行定量分析，以评估DMF平台上通过垂直和水平往复运动在摇晃液滴中的混合性能。此外，通过高速摄像系统成功地可视化了摇晃液滴内的混合流动模式。所提出的技术可以在基于液滴的微反应器中快速有效地混合样品和试剂，用于DMF应用，如生化分析和医学诊断。
