Anal Chem. 2013 Apr 16;85(8):3812-6. doi: 10.1021/ac400453t. Epub 2013 Mar 27.
Droplet-based fluidics is emerging as a powerful platform for single cell analysis, directed evolution of enzymes, and high throughput screening studies. Due to the small amounts of compound compartmentalized in each droplet, detection has been primarily by fluorescence. To extend the range of experiments that can be carried out in droplets, we have developed the use of electrospray ionization mass spectrometry (ESI-MS) to measure femtomole quantities of proteins in individual pico- to nanoliter droplets. Surfactant-stabilized droplets containing analyte were produced in a flow-focusing droplet generation microfluidic device using fluorocarbon oil as the continuous phase. The droplets were collected off-chip for storage and reinjected into microfluidic devices prior to spraying the emulsion into an ESI mass spectrometer. Crucially, high quality mass spectra of individual droplets were obtained from emulsions containing a mixture of droplets at >150 per minute, opening up new routes to high throughput screening studies.
基于液滴的流体学技术正在成为单细胞分析、酶的定向进化和高通量筛选研究的强大平台。由于每个液滴中分隔的化合物数量很少，因此主要通过荧光进行检测。为了扩展可以在液滴中进行的实验范围，我们已经开发了使用电喷雾电离质谱（ESI-MS）来测量单个皮升至纳升液滴中痕量蛋白质的方法。使用全氟碳油作为连续相，在流聚焦液滴生成微流控装置中产生含有分析物的表面活性剂稳定的液滴。将液滴从芯片上收集起来进行存储，并在将乳液喷射到 ESI 质谱仪之前重新注入微流控装置。至关重要的是，从每分钟含有 >150 个液滴的混合物的乳液中获得了高质量的单个液滴质谱，为高通量筛选研究开辟了新途径。
