A 'microfluidic pinball' for on-chip generation of Layer-by-Layer polyelectrolyte microcapsules
A 'microfluidic pinball' for on-chip generation of Layer-by-Layer polyelectrolyte microcapsules
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DOI：
10.1039/c0lc00381f
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发表时间：
2011-01-01
期刊：
影响因子：
6.1
通讯作者：
Trau, Dieter
中科院分区：
文献类型：
--
作者：
Kantak, Chaitanya;Beyer, Sebastian;Trau, Dieter
受“弹球”游戏的启发，滚动的金属球被障碍物引导，在这里，我们描述了一种新颖的微流控技术，该技术利用流道中的微柱来连续生成、封装和引导层层（LbL）聚电解质微胶囊。基于液滴的微流控技术被用来生成油滴，这些油滴被平稳地引导沿着一排微柱，重复地穿过由两种聚合物和洗涤剂组成的三个平行层流。设备在 PDMS 中进行原型设计，并生成高度单分散且稳定的 45 +/- 2 μm 大小的聚电解质微胶囊，在不到 3 分钟内每个液滴上吸附了总共六层氢键聚电解质，并且荧光强度测量证实了聚合物薄膜沉积，每个聚合物层的厚度约为 2.8 nm。此外，通过我们的设计，可以在不增加任何额外的操作或界面复杂性（例如注射泵）的情况下沉积大量的聚电解质多层（PEM），而这在大多数其他设计中是必需的，基于我们设备的上述优点，它可以开发成用于药物封装的出色工具，或用于创建用于生物传感的胶囊，其中沉积具有受控界面特性的纳米薄膜。要求很高。
Inspired by the game of "pinball'' where rolling metal balls are guided by obstacles, here we describe a novel microfluidic technique which utilizes micropillars in a flow channel to continuously generate, encapsulate and guide Layer-by-Layer (LbL) polyelectrolyte microcapsules. Droplet-based microfluidic techniques were exploited to generate oil droplets which were smoothly guided along a row of micropillars to repeatedly travel through three parallel laminar streams consisting of two polymers and a washing solution. Devices were prototyped in PDMS and generated highly monodisperse and stable 45 +/- 2 mu m sized polyelectrolyte microcapsules. A total of six layers of hydrogen bonded polyelectrolytes (3 bi-layers) were adsorbed on each droplet within < 3 minutes and a fluorescent intensity measurement confirmed polymer film deposition. AFM analysis revealed the thickness of each polymer layer to be approx. 2.8 nm. Our design approach not only provides a faster and more efficient alternative to conventional LbL deposition techniques, but also achieves the highest number of polyelectrolyte multilayers (PEMs) reported thus far using microfluidics. Additionally, with our design, a larger number of PEMs can be deposited without adding any extra operational or interfacial complexities (e. g. syringe pumps) which are a necessity in most other designs. Based on the aforementioned advantages of our device, it may be developed into a great tool for drug encapsulation, or to create capsules for biosensing where deposition of thin nanofilms with controlled interfacial properties is highly required.