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Microfluidic Emulsion Templating, Directional Solidification and Controlled Release

微流控乳液模板、定向凝固和控释

基本信息

批准号：
2292548
负责人：
金额：
--
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2292548
关键词：
Microfluidic Emulsion Templating Directional Solidification

项目摘要

Microcapsules and particles offer efficient means of carrying and delivering active ingredients, including medical drugs and cosmetics, with precise spatio-temporal release profiles. Mechanistic understanding of the encapsulation, solidification and release processes is crucial in designing future microcapsules, combining thermodynamics, mass transfer and non-equilibrium phenomena, including kinetic arrest or phase changes. Emulsion droplets, generated within microfluidic devices, which can form a barrier between the cargo and external environment can be used to template microcapsules from, by directional solidification processes, and are being investigated to tackle this challenge. Rapidly prototyped microfluidic devices, produced by frontal photopolymerization of thiol-ene resists, with flow-focussing geometries, and 200-600 micrometers dimensions, were used to generate single and double emulsion droplets from several polymeric, amphiphilic and hydrophobic species. Directional solidification processes, e.g. solvent extraction and ionic crosslinking, were exploited to form solid capsules from the droplets. The effects of varying process parameters, such as multivalent salt concentration or non-solvent quality, as well as the materials used on the solidification process and particle/capsule morphology was observed primarily by optical microscopy. Hydrogel particles (100-500 micrometers) were formed from single emulsion droplets of sodium carboxy methylcellulose (NaCMC) and solidified in multivalent salts. Gel particle formation was thought to be a result of aggregation of polymer chains; dictated by the interplay of shielding, ion bridging and charge inversion occurring upon salt addition. Solid polymer particles were also produced by a solvent extraction process; immersion of aqueous poly (vinyl alcohol) droplets, from a microfluidic single emulsion generator, into a non-solvent bath. Polymer concentration and non-solvent quality affected the morphology of the resultant particles and the kinetics of the directional solidification process. This versatility of this approach was shown by also solidifying aqueous NaCMC droplets into solid particles. Further understanding of these directional solidification processes, their response to changes in molecular structure, processing parameters and flow, will enable them to be applied to encapsulation. Double emulsion droplets with an inner core of hydrophobic material, can be solidified by these methods to produce solid shells. Their potential application in a wide range of industries, from pharmaceuticals to personal care, will be demonstrated by studying their controlled release properties.

微胶囊和颗粒提供了携带和递送活性成分的有效手段，包括医疗药物和化妆品，具有精确的时空释放曲线。对封装、固化和释放过程的机械理解在设计未来的微胶囊中至关重要，结合热力学、传质和非平衡现象，包括动力学停滞或相变。在微流体装置内产生的乳液液滴可以在货物和外部环境之间形成屏障，可以用于通过定向凝固过程形成微胶囊的模板，并且正在研究以应对这一挑战。快速原型化的微流体装置，由正面光聚合的硫醇-烯抗蚀剂，与流动聚焦的几何形状，和200-600微米的尺寸，被用来产生单和双乳液液滴从几个聚合物，两亲性和疏水性物种。定向固化过程，例如溶剂萃取和离子交联，被用来从液滴形成固体胶囊。不同的工艺参数，如多价盐浓度或非溶剂质量，以及所用的材料对固化过程和颗粒/胶囊形态的影响主要通过光学显微镜观察。水凝胶颗粒（100-500微米）由羧甲基纤维素钠（NaCMC）的单一乳液液滴形成并在多价盐中固化。凝胶颗粒的形成被认为是聚合物链聚集的结果;由盐添加后发生的屏蔽、离子桥接和电荷反转的相互作用决定。固体聚合物颗粒也通过溶剂萃取过程产生;将来自微流体单乳液发生器的水性聚（乙烯醇）液滴浸入非溶剂浴中。聚合物浓度和非溶剂质量影响所得颗粒的形态和定向凝固过程的动力学。这种方法的通用性也通过将水性NaCMC液滴固化成固体颗粒来显示。进一步了解这些定向凝固过程，它们对分子结构、工艺参数和流动变化的响应，将使它们能够应用于封装。具有疏水材料内核的双重乳液液滴可以通过这些方法固化以产生固体壳。它们在从制药到个人护理的广泛行业中的潜在应用将通过研究它们的控释特性来证明。