Department of Chemical and Biomolecular Engineering, KAIST, Daejeon, 305-701 Korea.
Lab Chip. 2012 Apr 21;12(8):1446-53. doi: 10.1039/c2lc00018k. Epub 2012 Mar 8.
Submicron emulsions could be produced via the tip-streaming process in a flow-focusing microfluidic device. In this article, the stability of the liquid cone and thread for tip-streaming mode could be significantly improved by employing a three-dimensional flow-focusing device, in which the hydraulic resistance was adjusted by modulating the channel heights in the flow focusing area, orifice, downstream and dispersed phase inlet channel. The pressure range for tip-streaming mode was enlarged significantly compared with two-dimensional flow-focusing devices. Therefore, monodisperse emulsions were produced under this tip-streaming mode for as long as 48 hours. Furthermore, we could control the size of emulsion drops by changing the pressure ratio in three-dimensional flow-focusing devices while the liquid cone was easily retracted during the adjustment of pressure ratio in two-dimensional flow-focusing devices. Furthermore, using the uniform submicron emulsion droplets as confining templates, polyethylene glycol (PEG) particles were produced with a narrow size distribution at the sub-micrometre scale. In addition, magnetic nanoparticles were added to the emulsion for magnetic PEG particles, which can respond to magnetic field and would be biocompatible.
亚微米乳液可以通过在流聚焦微流控装置中的射流过程产生。在本文中，通过采用三维流聚焦装置，可显著提高射流模式下的液体锥和螺纹的稳定性，其中通过调节流聚焦区域、孔口、下游和分散相入口通道中的通道高度来调整液压阻力。与二维流聚焦装置相比，射流模式的压力范围显著扩大。因此，在这种射流模式下可以长时间（长达 48 小时）产生单分散乳液。此外，我们可以通过改变三维流聚焦装置中的压力比来控制乳液液滴的大小，而在二维流聚焦装置中调节压力比时，液体锥很容易缩回。此外，使用均匀的亚微米乳液液滴作为限制模板，可以在亚微米尺度上生产具有窄粒径分布的聚乙二醇（PEG）颗粒。此外，向乳液中添加磁性纳米颗粒以形成磁性 PEG 颗粒，这些颗粒可以响应磁场并且具有生物相容性。
