Engineering Functional Microcapsules for Controlled Cargo Delivery

Abstract

Microcapsules are a tiny container on the order of 100 $\mu m$ with a typical structure made of an aqueous core and a solid shell. They are widely used in cargo delivery application because of its unique core-shell structure. Some fragile or expensive cargo molecules can be encapsulated inside the core of the capsules while being protected by the shell during transfer. And after these capsules are transferred to the target positions, some channels on the capsules shell will be triggered open by external signals to release the encapsulated cargo into the surrounding environment. Because of its characteristics of allowing for controlled release, protection of active ingredients as well as targeted delivery, microcapsules have applications in many different fields such as pharmaceuticals, food industry, cosmetics, and agriculture. One major application of microcapsules is for drug delivery. As an example, polysaccharide based microcapsules are developed for biomedical applications. Microcapsules with different tailored structures can be fabricated to encapsulate specific drugs. And after encapsulation, the surface of the capsules are being modified with specific ligands to target specific receptors on cellular membranes. The ligands on the microcapsules bind to the targeted receptors on the cells to ensure that the drug is delivered specifically to the intended site/position. And for the drug release step, the microcapsules can be designed to respond to specific conditions in the microenvironment, such as reactive oxygen species (ROS), glutathione (GSH), and pH levels, to trigger the release of the drug by external stimuli like ultrasound, light, or magnetic fields. Other applications of microcapsules include encapsulation and controlled release of flavors and vitamins in food industry, moisturizers and anti0aging compounds in cosmetics or pesticides and fertilizers in agriculture. In this dissertation, I'll present my PhD work on designing different core-shell structures as delivery vehicles from many different aspects such as the structural properties of capsule shell, adaptive response and versatility for different cargo sizes.