Monodisperse polyethylene glycol diacrylate hydrogel microsphere formation by oxygen-controlled photopolymerization in a microfluidic device.
Monodisperse polyethylene glycol diacrylate hydrogel microsphere formation by oxygen-controlled photopolymerization in a microfluidic device.
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DOI：
10.1039/c6lc00254d
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发表时间：
2016-04-21
期刊：
影响因子：
6.1
通讯作者：
Oakey J
中科院分区：
文献类型：
--
作者：
Krutkramelis K;Xia B;Oakey J
基于PEG的水凝胶已被广泛用作药物递送和组织支架材料。在PEG水凝胶形成聚合物中常见的是可光聚合的丙烯酸酯，例如聚乙二醇二丙烯酸酯（PEGDA）。微流体和微制造技术最近使得PEGDA结构的小型化成为可能，从而使得纳米和微米结构的水凝胶的许多可能的应用成为可能。然而，氧的存在显著地抑制PEGDA的光聚合，这又阻碍了水凝胶在持续高氧浓度的环境中的形成。使用PEGDA，已乳化在氟碳油通过微流体流动聚焦在聚二甲基硅氧烷（PDMS）设备，我们表明，聚合反应完全抑制低于临界液滴直径。通过开发一个集成的模型，将反应动力学和氧扩散，我们表明，临界液滴直径在很大程度上是由氧传输速率，这是由连续油相的氧饱和浓度决定。为了克服这一基本限制，我们提出了一种氮气微夹套微流体装置，以减少液滴内的氧气，从而实现微尺度PEGDA颗粒的连续芯片上光聚合。
PEG-based hydrogels have become widely used as drug delivery and tissue scaffolding materials. Common among PEG hydrogel-forming polymers are photopolymerizable acrylates such as polyethylene glycol diacrylate (PEGDA). Microfluidics and microfabrication technologies have recently enabled the miniaturization of PEGDA structures, thus enabling many possible applications for nano- and micro- structured hydrogels. The presence of oxygen, however, dramatically inhibits the photopolymerization of PEGDA, which in turn frustrates hydrogel formation in environments of persistently high oxygen concentration. Using PEGDA that has been emulsified in fluorocarbon oil via microfluidic flow focusing within polydimethylsiloxane (PDMS) devices, we show that polymerization is completely inhibited below critical droplet diameters. By developing an integrated model incorporating reaction kinetics and oxygen diffusion, we demonstrate that the critical droplet diameter is largely determined by the oxygen transport rate, which is dictated by the oxygen saturation concentration of the continuous oil phase. To overcome this fundamental limitation, we present a nitrogen micro-jacketed microfluidic device to reduce oxygen within the droplet, enabling the continuous on-chip photopolymerization of microscale PEGDA particles.