Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, Liaoning 116023, China.
Lab Chip. 2011 Mar 7;11(5):969-73. doi: 10.1039/c0lc00341g. Epub 2010 Dec 7.
A three-layer poly (methyl methacrylate) (PMMA) electrophoresis microchip integrated with Pt microelectrodes for contactless conductivity detection is presented. A 50 μm-thick PMMA film is used as the insulating layer and placed between the channel plate (containing the microchannel) and the electrode plate (containing the microelectrode). The three-layer structure facilitates the achievement of a thin insulating layer, obviates the difficulty of integrating microelectrodes on a thin film, and does not compromise the integration of microchips. To overcome the thermal and chemical incompatibilities of polymers and photolithographic techniques, a modified lift-off process was developed to integrate Pt microelectrodes onto the PMMA substrate. A novel two-step bonding method was created to assemble the complete PMMA microchip. A low limit of detection of 1.25 μg ml(-1) for Na(+) and high separation efficiency of 77,000 and 48,000 plates/m for Na(+) and K(+) were obtained when operating the detector at a low excitation frequency of 60 kHz.
提出了一种集成 Pt 微电极的三层聚甲基丙烯酸甲酯（PMMA）电泳微芯片，用于非接触式电导检测。使用 50μm 厚的 PMMA 薄膜作为绝缘层，放置在通道板（包含微通道）和电极板（包含微电极）之间。这种三层结构有利于实现薄的绝缘层，避免了在薄膜上集成微电极的困难，并且不影响微芯片的集成。为了克服聚合物和光刻技术的热和化学不兼容性，开发了一种改进的剥离工艺，将 Pt 微电极集成到 PMMA 基底上。创建了一种新颖的两步键合方法来组装完整的 PMMA 微芯片。当以低激发频率 60 kHz 操作检测器时，获得了 Na(+) 的低检测限 1.25μgml(-1)和 Na(+)和 K(+)的高分离效率 77,000 和 48,000 板/m。
