Electrokinetic control of fluid flow in native poly(dimethylsiloxane) capillary electrophoresis devices
Electrokinetic control of fluid flow in native poly(dimethylsiloxane) capillary electrophoresis devices
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DOI：
10.1002/(sici)1522-2683(20000101)21:1
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发表时间：
2000
期刊：
影响因子：
2.9
通讯作者：
G. Ocvirk;Mark Munroe;T. Tang;R. Oleschuk;K. Westra;D. J. Harrison
中科院分区：
文献类型：
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作者：
G. Ocvirk;Mark Munroe;T. Tang;R. Oleschuk;K. Westra;D. J. Harrison
用聚二甲基硅氧烷（PDMS）制造的毛细管区带电泳（CZE）装置需要对流体网络中所有相交通道进行连续电压控制，以避免在相交处发生灾难性泄漏。这与在玻璃基板上制造的类似流道设计的行为形成对比。当注射塞通过电压控制成型，分离过程中通过施加反压电压控制侧通道泄漏时，荧光素样品给出64200个理论极板（7000 V分离电压，E = 1340 V/cm）。当充满水时，原生PDMS设备在五天内表现出稳定的保留时间（±8.6% RSD）。在16周的干燥储存期间，接触角保持不变（±1.9% RSD），这与等离子体氧化PDMS表面的已知行为形成了对比。在所研究的缓冲体系（磷酸盐，pH 3-10.5）中，无论是否存在疏水离子（如四丁基铵或十二烷基硫酸盐），都观察到阴极方向的电渗透流动（EOF）。在pH值为3和10.5时，电渗透迁移率分别为1.49 × 10-5和5.84 × 10-4 cm2/Vs，这一变化强烈表明聚合物中的二氧化硅填料主导了材料的zeta电位。疏水化合物如十二烷基硫酸盐和BODIPY®493/503强烈吸附在PDMS上，表明通道壁的疏水性对于疏水分析物的CZE分析显然是有问题的。本文还描述了一种在PDMS中实现多信道层叠加的方法。
Capillary zone electrophoresis (CZE) devices fabricated in poly(dimethylsiloxane) (PDMS) require continuous voltage control of all intersecting channels in the fluidic network in order to avoid catastrophic leakage at the intersections. This contrasts with the behavior of similar flow channel designs fabricated in glass substrates. When the injection plugs are shaped by voltage control and leakage from side channels is controlled by the application of pushback voltages during separation, fluorescein samples give 64 200 theoretical plates (7000 V separation voltage, E = 1340 V/cm). Native PDMS devices exhibit stable retention times (± 8.6% RSD) over a period of five days when filled with water. Contact angles were unchanged (± 1.9% RSD) over a period of 16 weeks of dry storage, in contrast to the known behavior of plasma‐oxidized PDMS surfaces. Electroosmotic flow (EOF) was observed in the direction of the cathode for the buffer systems studied (phosphate, pH 3—10.5), in the presence or absence of hydrophobic ions such as tetrabutylammonium or dodecyl sulfate. Electroosmotic mobilities of 1.49 × 10—5 and 5.84 × 10—4 cm2/Vs were observed on average at pH 3 and 10.5, respectively, the variation strongly suggesting that silica fillers in the polymer dominate the zeta potential of the material. Hydrophobic compounds such as dodecyl sulfate and BODIPY® 493/503 adsorbed strongly to the PDMS, indicating the hydrophobicity of the channel walls is clearly problematic for CZE analysis of hydrophobic analytes. A method to stack multiple channel layers in PDMS is also described.