Composite Colloidal Particles Produced by Carbon Dioxide Assisted Microencapsulation

微胶囊化是将添加剂包埋在胶体颗粒中的过程。该技术被广泛应用于延长药物或香料等被捕获化合物的释放。然而，微胶囊化可用于生产具有可控光学、化学或物理性质的复合颗粒，用于多种应用。目前的微胶囊技术通常需要难以从聚合物中去除的有机溶剂。在最大允许浓度很低的食品和药品应用中，残留溶剂尤其不可取。我们建议研究添加剂进入分散在液体或超临界二氧化碳和水的乳液中的胶体聚合物颗粒的运输，以减少或消除对有机溶剂的需求。在高压下，二氧化碳膨胀并使聚合物颗粒塑化，促进质量运输。表面活性剂用于稳定二氧化碳和水的乳液。表面活性剂还吸附在颗粒表面以增强胶体稳定性。减压后，聚合物颗粒恢复到原来的大小和形状，包裹添加剂。吸附的表面活性剂留在表面，从而提供了控制颗粒表面化学性质的途径。在二氧化碳、水和无毒表面活性剂的帮助下，将药物、发色团和发光纳米粒子浸渍在可生物降解和生物相容性的聚合物胶体中。此外，我们建议将CO2处理与传统的微胶囊技术结合起来，以降低残留溶剂含量并对聚合物颗粒进行灭菌。拟议的研究将为复合颗粒的生产提供一种灵活的、生物和环境友好的途径，这些复合颗粒用于药物输送装置、药物发现和基因组学的示踪剂和指示器，以及其他用于催化、涂层和光学材料的复合胶体颗粒。为了扩大拟议研究的影响，在商业教育软件供应商的帮助下，将开发一个基于微封装技术的计算机教学模块，并将其纳入罗切斯特大学的“界面工程”课程。软件供应商表示有兴趣将该模块合并到他们现有的软件中，以进行更广泛的分发。来自不同背景的本科生和研究生将通过罗切斯特大学现有的项目参与该项目。

Microencapsulation is the process of embedding an additive in a colloidal particle.This technology is widely used to provide extended release of entrapped compounds suchas drugs or fragrances. However, microencapsulation may be used to produce compositeparticles with controlled optical, chemical, or physical properties for a wealth ofapplications. Current microencapsulation technology typically requires organic solventsthat are difficult to remove from the polymer. Residual solvent is especially undesirable forfood and drug applications where the maximum allowable concentration is very low. Wepropose to study the transport of additives into colloidal polymer particles dispersed in anemulsion of liquid or supercritical carbon dioxide and water in an effort to reduce oreliminate the need for organic solvents. At elevated pressures, carbon dioxide swells andplasticizes the polymer particles, facilitating mass transport. Surfactants are used tostabilize the emulsion of CO2 and water. The surfactants also adsorb on the surface of theparticles to enhance colloidal stability. After depressurization, the polymer particles returnto their original size and shape, entrapping the additive. The adsorbed surfactant remainson the surface and thus offers a route to controlling the surface chemistry of the particles.Biodegradable and biocompatible polymer colloids will be impregnated with drugs,chromophores, and luminescent nanoparticles with the aid of CO2, water, and non-toxicsurfactants. In addition, we propose to couple CO2 processing with traditionalmicroencapsulation techniques to lower residual solvent content and sterilize polymerparticles. The proposed research will provide a flexible, biologically and environmentallyfriendly route to the production of composite particles used as devices for drug delivery,tracers and indicators for drug discovery and genomics, and other composite colloidalparticles useful for catalysis, coatings, and optical materials. To broaden the impact of theproposed research, a computer based instructional module on microencapsulationtechnology will be developed and incorporated into the course 'Interfacial Engineering' atthe University of Rochester with the assistance of a commercial educational softwarevendor. The software vendor has expressed interest in incorporating the module into theirexisting software for broader distribution. Undergraduate and graduate students fromdiverse backgrounds will be recruited to work on the project through existing programs atthe University of Rochester.