Rounded multi-level microchannels with orifices made in one exposure enable aqueous two-phase system droplet microfluidics
Rounded multi-level microchannels with orifices made in one exposure enable aqueous two-phase system droplet microfluidics
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DOI：
10.1039/c1lc20560a
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发表时间：
2011-01-01
期刊：
影响因子：
6.1
通讯作者：
Takayama, Shuichi
中科院分区：
文献类型：
--
作者：
Lai, David;Frampton, John P.;Takayama, Shuichi
负性光致抗蚀剂涂覆的载玻片用漫射光从背面通过具有断开特征的掩模曝光，在一次曝光中提供了具有窄孔的多级圆形通道。使用这些结构，我们构建了能够产生含水两相系统液滴的微流体系统，其中一个水相形成液滴，另一个水相形成周围的基质。与油包水液滴系统不同，含水两相系统可以具有非常低的界面张力，从而防止自发的液滴形成。通过背面光刻制造的多级通道满足两个冲突的需求：（i）具有窄通道以通过通道变形实现有效阀关闭的需求，以及（ii）具有宽通道以降低流速的需求，从而减少毛细管数并增强液滴形成。
Exposure of a negative photoresist-coated glass slide with diffused light from the backside through a mask with disconnected features provides multi-level rounded channels with narrow orifices in one exposure. Using these structures, we construct microfluidic systems capable of creating aqueous two-phase system droplets where one aqueous phase forms droplets and the other aqueous phase forms the surrounding matrix. Unlike water-in-oil droplet systems, aqueous two-phase systems can have very low interfacial tensions that prevent spontaneous droplet formation. The multi-level channels fabricated by backside lithography satisfy two conflicting needs: (i) the requirement to have narrowed channels for efficient valve closure by channel deformation and (ii) the need to have wide channels to reduce the flow velocity, thus reducing the capillary number and enhancing droplet formation.