Hattori Koji, Sugiura Shinji, Kanamori Toshiyuki
Research Center of Advanced Bionics, National Institute of Advanced Industrial Science and Technology (AIST), Central 5th, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Lab Chip. 2009 Jun 21;9(12):1763-72. doi: 10.1039/b816995k. Epub 2009 Mar 13.
This paper reports a serial dilution microfluidic network composed of microchannels with a high fluidic-resistance ratio for generating linear concentration profiles as well as logarithmic concentration profiles spanning 3 and 6 orders of magnitude. The microfluidic networks were composed of thin fluidic-resistance microchannels with 160 to 730 microm(2) cross-sectional areas and thick diffusion-mixing microchannels with 3,600 to 17,000 microm(2) cross-sectional areas, and were fabricated from polydimethylsiloxane by multilayer photolithography and replica molding. We proposed a design algorithm of the microfluidic network for an arbitrary monotonic concentration profile by means of a hydrodynamic calculation. Because of the high fluidic-resistance ratio of the fluidic-resistance microchannels to the diffusion-mixing microchannels, appropriate geometry and dimensions of the fluidic-resistance microchannels allowed us to obtain desired concentration profiles. The fabricated microfluidic network was compact, occupying a 8 x 18 to 21.0 x 13.5 mm(2) area on the microchip. Both the linear and the logarithmic concentration profiles were successfully generated with the error less than 15% for the linear concentration profile, 22% and 35% for the logarithmic concentration profiles of 3 and 6 orders of magnitude, respectively. The generated linear concentration profiles of the small molecule, calcein, were independent of the flow rate within the range of 0.009 to 0.23 microL/min. The concentration profiles of the large molecules, dextrans, depended on the flow rate and molecular weight. The required residence time of large molecules in the diffusion-mixing microchannel was correlated with dimensionless diffusion time, Fick number, and was discussed based on the scaling law. These compact, stable serial dilution microfluidic networks are expected to be applied to various integrated on-chip analyses.
本文报道了一种由具有高流体阻力比的微通道组成的系列稀释微流控网络，用于生成线性浓度分布以及跨越3个和6个数量级的对数浓度分布。该微流控网络由横截面面积为160至730微米²的薄流体阻力微通道和横截面面积为3600至17000微米²的厚扩散混合微通道组成，并通过多层光刻和复制模塑由聚二甲基硅氧烷制成。我们通过流体动力学计算提出了一种用于任意单调浓度分布的微流控网络设计算法。由于流体阻力微通道与扩散混合微通道的高流体阻力比，流体阻力微通道的适当几何形状和尺寸使我们能够获得所需的浓度分布。所制造的微流控网络结构紧凑，在微芯片上占据8×18至21.0×13.5毫米²的面积。成功生成了线性和对数浓度分布，线性浓度分布的误差小于15%，3个数量级和6个数量级对数浓度分布的误差分别为22%和35%。所生成的小分子钙黄绿素的线性浓度分布在0.009至0.23微升/分钟的流速范围内与流速无关。大分子葡聚糖的浓度分布取决于流速和分子量。大分子在扩散混合微通道中所需的停留时间与无量纲扩散时间、菲克数相关，并基于标度定律进行了讨论。这些紧凑、稳定的系列稀释微流控网络有望应用于各种集成芯片分析。
