Kuo Chen-Hua, Wang Jung-Hao, Lee Gwo-Bin
Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan.
Electrophoresis. 2009 Sep;30(18):3228-35. doi: 10.1002/elps.200900112.
A simple, sequential DNA pre-concentration and separation method by using a micro-CE chip integrated with a normally closed valve, which is activated by pneumatic suction, has been developed. The CE chip is fabricated using PDMS. A surface treatment technique for coating a polymer bilayer with an anionic charge is applied to modify the surface of the microchannel. A normally closed valve with anionic surface charges forms a nanoscale channel that only allows the passage of electric current but traps the DNA samples so that they are pre-concentrated. After the pre-concentration step, a pneumatic suction force is applied to the normally closed valve. This presses down the valve membrane, which reconnects the channels. The DNA samples are then moved into a separation channel for further separation and analysis. Successful DNA pre-concentration and separation has been achieved. Fluorescent intensity at the pre-concentration area is increased by approximately 3570 times within 1.9 min of operation. The signals from the separation of phiX174 DNA/HaeIII markers are enhanced approximately 41 times after 100 s of pre-concentration time, as compared with the results using a traditional cross-shaped micro-CE chip. These results clearly demonstrate that successful DNA pre-concentration for signal enhancement and separation analysis can be performed by using this new micro-CE chip.
已经开发出一种简单的、连续的DNA预浓缩和分离方法，该方法使用集成有常闭阀的微流控芯片，该阀由气动抽吸激活。该微流控芯片采用聚二甲基硅氧烷（PDMS）制造。应用一种用于涂覆带阴离子电荷的聚合物双层的表面处理技术来修饰微通道的表面。具有阴离子表面电荷的常闭阀形成一个纳米级通道，该通道仅允许电流通过，但捕获DNA样品，从而对其进行预浓缩。在预浓缩步骤之后，对常闭阀施加气动吸力。这会压下阀膜，重新连接通道。然后将DNA样品移入分离通道进行进一步的分离和分析。已成功实现DNA的预浓缩和分离。在1.9分钟的操作时间内，预浓缩区域的荧光强度增加了约3570倍。与使用传统十字形微流控芯片的结果相比，在预浓缩100秒后，phiX174 DNA/HaeIII标记物分离的信号增强了约41倍。这些结果清楚地表明，使用这种新型微流控芯片可以成功地进行DNA预浓缩以增强信号并进行分离分析。
