Collision and Coalescence of Single Attoliter Oil Droplets on a Pipet Nanopore.
Collision and Coalescence of Single Attoliter Oil Droplets on a Pipet Nanopore.
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DOI：
10.1021/acs.langmuir.7b04090
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发表时间：
2018-02
期刊：
影响因子：
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通讯作者：
Christopher G Gunderson;Zhuoyu Peng;Bo Zhang
中科院分区：
文献类型：
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作者：
Christopher G Gunderson;Zhuoyu Peng;Bo Zhang
我们描述了使用石英吸管纳米孔来研究单个乳液油滴的碰撞和聚结及其随后的纳米孔易位。纳米孔口处单个甲苯液滴的碰撞和聚结主要由电渗和电泳驱动，并导致捕获的油滴快速生长。由于聚结的油滴增加了其体积及其部分阻挡纳米孔离子电流的能力，这导致了逐步的电流响应，从而使我们能够使用电阻脉冲方法来解决单滴碰撞。被捕获的油滴的进一步生长导致纳米孔完全堵塞和几乎 100% 的电流衰减。被捕获的油滴在较低电压下表现出巨大的机械稳定性，并保持捕获状态数百秒。增加的电压可用于在几毫秒内将捕获的液滴驱动到移液管孔中。同时进行荧光成像和电流分析来检查液滴碰撞、聚结和易位，进一步证实了所提出的液滴-纳米孔相互作用的机制。此外，我们展示了对纳米孔支持的阿托升油滴进行快速伏安测量并研究其电压驱动的离子转移过程的独特能力。
We describe the use of a quartz pipet nanopore to study the collision and coalescence of individual emulsion oil droplets and their subsequent nanopore translocation. Collision and coalescence of single toluene droplets at a nanopore orifice are driven primarily by electroosmosis and electrophoresis and lead to the fast growth of a trapped oil droplet. This results in a stepwise current response due to the coalesced oil droplet increasing its volume and its ability to partially block the nanopore's ionic current, allowing us to use the resistive-pulse method to resolve single droplet collisions. Further growth of the trapped oil droplet leads to a complete blockage of the nanopore and a nearly 100% current decay. The trapped oil droplet shows enormous mechanical stability at lower voltages and stays in its trapped status for hundreds of seconds. An increased voltage can be used to drive the trapped droplet into the pipet pore within several milliseconds. Simultaneous fluorescence imaging and amperometry were performed to examine droplet collision, coalescence, and translocation, further confirming the proposed mechanism of droplet-nanopore interaction. Moreover, we demonstrate the unique ability to perform fast voltammetric measurements on a nanopore-supported attoliter oil droplet and study its voltage-driven ion transfer processes.