%0 Online Multimedia
%A Zhang, Kai
%A Liang, Qionglin
%A Ai, Xiaoni
%A Hu, Ping
%A Wang, Yiming
%A Luo, Guoan
%D 2011
%T Comprehensive Two-Dimensional Manipulations of Picoliter Microfluidic Droplets Sampled from Nanoliter Samples
%U https://acs.figshare.com/articles/media/Comprehensive_Two_Dimensional_Manipulations_of_Picoliter_Microfluidic_Droplets_Sampled_from_Nanoliter_Samples/2601823
%R 10.1021/ac2017458.s003
%2 https://acs.figshare.com/ndownloader/files/4250686
%K Picoliter Microfluidic Droplets Sampled
%K droplet manipulations
%K method
%K droplet arrays
%K microwell
%X 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 ±X-direction and ±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.
%I ACS Publications