Comprehensive Two-Dimensional Manipulations of Picoliter Microfluidic Droplets Sampled from Nanoliter Samples

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• 作者：Kai Zhang ; Qionglin Liang ; Xiaoni Ai ; Ping Hu ; Yiming Wang ; Guoan Luo
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：October 15, 2011
• 年：2011
• 卷：83
• 期：20
• 页码：8029-8034
• 全文大小：891K
• 年卷期：v.83,no.20(October 15, 2011)
• ISSN：1520-6882

文摘

A facile method is presented for achieving comprehensive two-dimensional droplet manipulations in closed microstructures consisting of microwell arrays and a straight microchannel. In this method, picoliter/nanoliter droplets with controllable sizes and numbers are sampled from nanoliter samples/reagents with almost 100% efficiency. Droplet motions are precisely controlled in the 卤X-direction and 卤Y-direction by managing hydrostatic pressure and magnetic repulsion, respectively. As a demonstration, a fluorescein-labeled droplet and a deionized droplet are successively generated and trapped in adjacent microwells. Then their positions are quickly exchanged without cross-contamination and fusion is implemented on-demand. After operations, hydrophobic ferrofluid can be completely replaced by mineral oil and droplets still remain in microwells safely. A typical fluorescence intensity-based assay is demonstrated: droplet arrays containing copper ion are diluted disproportionately first and then detected by addition of droplet arrays containing Calcein. With the ability of comprehensive two-dimensional droplet manipulations, this method could be used in various miniaturized biochemical analyses including requirements of multistep procedures and in situ monitoring.