Flachsbart Bruce R, Wong Kachuen, Iannacone Jamie M, Abante Edward N, Vlach Robert L, Rauchfuss Peter A, Bohn Paul W, Sweedler Jonathan V, Shannon Mark A
Department of Mechanical & Industrial Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Lab Chip. 2006 May;6(5):667-74. doi: 10.1039/b514300d. Epub 2006 Mar 17.
The design and fabrication of a multilayered polymer micro-nanofluidic chip is described that consists of poly(methylmethacrylate) (PMMA) layers that contain microfluidic channels separated in the vertical direction by polycarbonate (PC) membranes that incorporate an array of nanometre diameter cylindrical pores. The materials are optically transparent to allow inspection of the fluids within the channels in the near UV and visible spectrum. The design architecture enables nanofluidic interconnections to be placed in the vertical direction between microfluidic channels. Such an architecture allows microchannel separations within the chip, as well as allowing unique operations that utilize nanocapillary interconnects: the separation of analytes based on molecular size, channel isolation, enhanced mixing, and sample concentration. Device fabrication is made possible by a transfer process of labile membranes and the development of a contact printing method for a thermally curable epoxy based adhesive. This adhesive is shown to have bond strengths that prevent leakage and delamination and channel rupture tests exceed 6 atm (0.6 MPa) under applied pressure. Channels 100 microm in width and 20 microm in depth are contact printed without the adhesive entering the microchannel. The chip is characterized in terms of resistivity measurements along the microfluidic channels, electroosmotic flow (EOF) measurements at different pH values and laser-induced-fluorescence (LIF) detection of green-fluorescent protein (GFP) plugs injected across the nanocapillary membrane and into a microfluidic channel. The results indicate that the mixed polymer micro-nanofluidic multilayer chip has electrical characteristics needed for use in microanalytical systems.
本文描述了一种多层聚合物微纳流体芯片的设计与制造,该芯片由聚甲基丙烯酸甲酯(PMMA)层组成,其中包含微流体通道,这些通道在垂直方向上被聚碳酸酯(PC)膜隔开,PC膜中包含一系列纳米直径的圆柱形孔。这些材料具有光学透明性,可在近紫外和可见光谱范围内检查通道内的流体。该设计架构使纳米流体互连能够在微流体通道之间垂直放置。这种架构允许在芯片内进行微通道分离,还允许利用纳米毛细管互连进行独特操作:基于分子大小分离分析物、通道隔离、增强混合和样品浓缩。通过不稳定膜的转移过程以及开发用于热固化环氧基粘合剂的接触印刷方法,实现了器件制造。这种粘合剂的粘结强度可防止泄漏和分层,在施加压力下,通道破裂测试超过6个大气压(0.6兆帕)。宽度为一百微米、深度为二十微米的通道通过接触印刷形成,且粘合剂不会进入微通道。该芯片通过沿微流体通道的电阻率测量、不同pH值下的电渗流(EOF)测量以及对注入纳米毛细管膜并进入微流体通道的绿色荧光蛋白(GFP)塞子的激光诱导荧光(LIF)检测来表征。结果表明,这种混合聚合物微纳流体多层芯片具有微分析系统所需的电学特性。