Fundamental studies of adhesion phenomena involving vesicles

囊泡是微米或纳米大小的颗粒，它们借助边界膜将有限体积的液体分隔开来。以囊泡为基础的产品，如织物柔软剂、护肤霜、护发液，以及治疗药物，如Doxil（化疗药物）和两性霉素（抗真菌药物），在全球范围内构成了数十亿美元的业务。然而，由于其中许多产品的开发都是反复试验、以实验为重点的，因此，对于哪些因素会导致更少的原材料消耗、更有效的资源利用、更低的环境影响和更好的产品功能，仍然缺乏一个基本的了解。这个项目代表了对上述关系进行系统理解的第一步。特别是，我们专注于一个现象，支配优化的囊泡为基础的产品-囊泡粘附（即囊泡粘）。囊泡粘附是产品功能的关键步骤，如乳液和治疗剂；另一方面，它对织物柔顺剂等产品是一种威胁，并导致这些产品中的活性物质起霜或沉淀。

Vesicles are micron or nanometer-sized particles which compartmentalize a finite volume of liquid with the help of a bounding membrane. Vesicle-based products such as fabric softeners, skin creams, hair lotions, and therapeutics such as Doxil (chemotherapeutic) and Amphotericin (antifungal) together constitute a multi-billion dollar business worldwide. However, due to the trial-and-error, experimentally-focused nature of development of many of these products, a fundamental understanding of what factors would lead to lesser raw material consumption, more efficient resource usage, lower environmental impact and better product function is still lacking. This project represents a first step towards the development of a systematic understanding of the above relationships. In particular, we focus on one phenomenon that governs optimization of vesicle-based products - vesicle adhesion (i.e. vesicle sticking). Vesicle adhesion is a crucial step in the function of products such as lotions and therapeutics; on the other hand, it is a menace for products such as fabric softeners, and leads to creaming or settling of the active material in these products. In this project, we will develop two tools that will characterize vesicle adhesion phenomena. One is a flow device called the microfluidic four-roll mill, which will help us understand how flow induces or prevents the adhesion of vesicles. The other device is a force apparatus, which determines how strongly or weakly a vesicle binds to a surface or another vesicle. The theoretical component of this project will formulate models and simulations that will predict the conditions which enhance or prevent vesicle adhesion. The tools and results from this project will impact a wide variety of fields other than vesicle-product industries. The interactions between biological cells and surfaces with and without flow have implications in blood flow, immunological response mechanisms, intra and intercellular transport, drug delivery and tissue engineering. Our tools will also be applicable for designing emulsion systems which are prevalent in the food, vegetable oil and petroleum industries, all billion dollar industries in Canada.