Lee Gwo-Bin, Lin Che-Hsin, Lee Kuo-Hoong, Lin Yue-Feng
Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan.
Electrophoresis. 2005 Dec;26(24):4616-24. doi: 10.1002/elps.200500382.
This paper presents systematic investigation of the microchannel surface properties in microCE chips. Three popular materials for microCE chips, polydimethylsiloxane (PDMS), quartz, and glass, are used. The zeta potentials of these microchannels are calculated by measuring the EOF velocity to evaluate the surface properties after surface modification. The hydrophobic PDMS is usually plasma-treated for microCE applications. In this study, a new method using a high-throughput atmospheric plasma generator is adopted to treat the PDMS surface under atmospheric conditions. In this approach, the cost and time for surface treatment can be significantly reduced compared with the conventional vacuum plasma generator method. Experimental results indicate that new functional groups could be formed on the PDMS surface after treatment, resulting in a change in the surface property. The time-dependent surface property of the plasma-treated PDMS is then measured in terms of the zeta potential. Results show that the surface property will reach a stable condition after 1 h of plasma treatment. For glass CE chips, two new methods for changing the microchannel surface properties are developed. Instead of using complicated and time-consuming chemical silanization procedures for CE channel surface modification, two simple and reliable methods utilizing organic-based spin-on-glass and water-soluble acrylic resin are reported. The proposed method provides a fast batch process for controlling the surface properties of glass-based CE channels. The proposed methods are evaluated using PhiX-174 DNA maker separation. The experimental data show that the surface property is modified and separation efficiency greatly improved. In addition, the long-term stability of both coatings is verified in this study. The methods proposed in this study show potential as an excellent solution for glass-based microCE chip surface modification.
本文介绍了对微流控芯片中微通道表面特性的系统研究。使用了三种常用于微流控芯片的材料，聚二甲基硅氧烷（PDMS）、石英和玻璃。通过测量电渗流速度来计算这些微通道的zeta电位，以评估表面改性后的表面特性。疏水性的PDMS通常用于微流控应用的等离子体处理。在本研究中，采用一种使用高通量大气等离子体发生器的新方法，在大气条件下处理PDMS表面。与传统的真空等离子体发生器方法相比，这种方法可以显著降低表面处理的成本和时间。实验结果表明，处理后PDMS表面可形成新的官能团，导致表面性质发生变化。然后根据zeta电位测量等离子体处理的PDMS随时间变化的表面性质。结果表明，等离子体处理1小时后表面性质将达到稳定状态。对于玻璃微流控芯片，开发了两种改变微通道表面性质的新方法。报道了两种简单可靠的方法，利用有机旋涂玻璃和水溶性丙烯酸树脂，而不是使用复杂且耗时的化学硅烷化程序对微流控通道表面进行改性。所提出的方法为控制基于玻璃的微流控通道的表面性质提供了一种快速批量处理方法。使用PhiX-174 DNA标记物分离对所提出的方法进行了评估。实验数据表明表面性质得到了改性，分离效率大大提高。此外，本研究还验证了两种涂层的长期稳定性。本研究中提出的方法显示出作为基于玻璃的微流控芯片表面改性的优异解决方案的潜力。
