Netherlands Metabolomics Centre (NMC), Leiden Academic Centre for Drug Research (LACDR), Einsteinweg 55, 2333CC, Leiden, The Netherlands.
Lab Chip. 2013 Dec 21;13(24):4810-5. doi: 10.1039/c3lc50658d.
Elastomeric microvalves in poly(dimethylsiloxane) (PDMS) devices are today's paradigm for massively parallel microfluidic operations. Here, we report that such valves can act as nanochannels upon closure. When tuning nanospace heights between ~55 nm and ~7 nm, the nanofluidic phenomenon of concentration polarization could be induced. A wide range of concentration polarization regimes (anodic and cathodic analyte focusing and stacking) was achieved simply by valve pressure actuation. Electro-osmotic flow generated a counterpressure which also could be used to actuate between concentration polarization regimes. 1000-fold preconcentration of fluorescein was achieved in just 100 s in the anodic focusing regime. After valve opening, a concentrated sample plug could be transported through the valve, though at the cost of some defocusing. Reversible nanochannels open new avenues for integrating electrokinetic operations and assays in large scale integrated microfluidics.
弹性微阀在聚二甲基硅氧烷（PDMS）器件中是目前大规模并行微流控操作的范例。在这里，我们报告说，这些阀在关闭时可以充当纳米通道。当调节纳米空间高度在55nm 到7nm 之间时，可以诱导纳流体力学中的浓度极化现象。通过简单的阀压致动，实现了广泛的浓度极化区（阳极和阴极分析物聚焦和堆积）。通过电渗流产生的反压也可以用于在浓度极化区之间进行致动。在阳极聚焦区中，仅 100 秒即可实现对荧光素的 1000 倍预浓缩。在阀打开后，可以通过阀输送浓缩的样品塞，但代价是一些散焦。可逆纳米通道为在大规模集成微流控中集成电动操作和分析开辟了新途径。
