Biomicrofluidics. 2012 Mar;6(1):16503-1650313. doi: 10.1063/1.3683163. Epub 2012 Feb 10.
Recent studies show that reduction in cross-sectional area can be used to improve the concentration factor in microscale bioseparations. Due to simplicity in fabrication process, a step reduction in cross-sectional area is generally implemented in microchip to increase the concentration factor. But the sudden change in cross-sectional area can introduce significant band dispersion and distortion. This paper reports a new fabrication technique to form a gradual reduction in cross-sectional area in polymethylmethacrylate (PMMA) microchannel for both anionic and cationic isotachophoresis (ITP). The fabrication technique is based on hot embossing and surface modification assisted bonding method. Both one-dimensional and two-dimensional gradual reduction in cross-sectional area microchannels were formed on PMMA with high fidelity using proposed techniques. ITP experiments were conducted to separate and preconcentrate fluorescent proteins in these microchips. Thousand fold and ten thousand fold increase in concentrations were obtained when 10 × and 100 × gradual reduction in cross-sectional area microchannels were used for ITP.
最近的研究表明，减少横截面面积可以用于提高微尺度生物分离中的浓缩因子。由于制造工艺简单，通常在微芯片中采用横截面面积的阶跃式减小来增加浓缩因子。但是，横截面面积的突然变化会引入显著的带宽分散和失真。本文报道了一种新的制造技术，用于在聚甲基丙烯酸甲酯（PMMA）微通道中形成阴离子和阳离子等速电泳（ITP）的逐渐减小的横截面面积。该制造技术基于热压印和表面改性辅助键合方法。使用提出的技术，在 PMMA 上以高精度形成了一维和二维逐渐减小的横截面面积微通道。在这些微芯片中进行了 ITP 实验，以分离和预浓缩荧光蛋白。当使用 10×和 100×逐渐减小的横截面面积微通道进行 ITP 时，浓度分别提高了千倍和万倍。
