Composite Colloidal Particles Produced by Carbon Dioxide Assisted Microencapsulation

微胶囊化是在胶体颗粒中嵌入添加剂的过程。这项技术被广泛用于提供药物或香料等被包裹的化合物的延长释放。然而，微胶囊可用于生产具有受控光学、化学或物理性质的复合粒子，以用于大量应用。目前的微胶囊技术通常需要很难从聚合物中去除的有机溶剂。残留溶剂对于最大允许浓度非常低的食品和药品应用尤其不可取。我们建议研究添加剂在分散在液体或超临界二氧化碳和水的乳状液中的胶体聚合物颗粒中的传输，以努力减少或减少对有机溶剂的需求。在高压下，二氧化碳膨胀并塑化聚合物颗粒，促进质量传输。表面活性剂被用来稳定二氧化碳和水的乳状液。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，包埋在添加剂中。吸附的表面活性剂留在表面，从而提供了一种控制颗粒表面化学的途径。可生物降解和生物相容的聚合物胶体将在二氧化碳、水和无毒表面活性剂的帮助下浸渍药物、生色团和发光纳米颗粒。此外，我们建议将二氧化碳处理与传统微胶囊化技术相结合，以降低残留溶剂含量并对聚合物颗粒进行灭菌。这项拟议的研究将提供一种灵活的、生物和环境友好的方法来生产复合颗粒，用作药物输送设备、药物发现和基因组学的示踪剂和指示剂，以及用于催化、涂层和光学材料的其他复合胶体颗粒。为了扩大拟议研究的影响，将在一家商业教育软件供应商的帮助下，开发一个关于微囊化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。这家软件供应商表示有兴趣将该模块整合到他们现有的软件中，以便更广泛地分发。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被招募参与该项目。

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.