Digital microfluidics has the potential to minimize and automate reactions in biochemical labs. However, the complexity of drop manipulation and sample preparation on-chip has limited its incorporation into daily workflow. In this paper, we report a novel method for flexible sample delivery on digital microfluidics in a wide volume range spanning four orders of magnitude from picoliters to nanoliters. The method is based on the phenomenon of satellite droplet ejection, triggered by a sudden change in the strength of the electric field across a drop on a hydrophobic dielectric surface. By precisely modulating the actuation signal with convenient external electric controls, satellite droplet ejection can be turned on to dispense samples or turned off to transport picking-up drops. A pico-dosing design is presented and validated in this work to demonstrate the direct and flexible on-chip sample delivery. This approach could pave the way for the acceptance of microfluidics as a common platform for daily reactions to realize lab-on-a-chip.

中文翻译：

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开启/关闭卫星液滴喷射以在数字微流控系统上灵活地传输样品

数字微流控技术具有使生化实验室中的反应最小化和自动化的潜力。但是，液滴操作和片上样品制备的复杂性限制了其在日常工作流程中的应用。在本文中，我们报告了一种新颖的方法，可以在从皮升到纳升的四个数量级的大体积范围内的数字微流体上灵活地进行样品输送。该方法基于卫星液滴喷射现象，该现象是由疏水介电表面上的液滴两端的电场强度突然变化触发的。通过使用方便的外部电子控制装置精确调制致动信号，可以打开卫星液滴喷射以分配样品，或者关闭卫星液滴喷射以传输拾取液滴。在这项工作中提出并验证了微剂量设计，以演示直接且灵活的片上样品交付。这种方法可以为接受微流体作为实现日常反应的通用平台铺平道路，以实现芯片实验室。