Self Destructing "Mothership" Capsules for Timed Release of Encapsulated Contents

Abstract

This thesis explores a new class of hierarchical containers that are formed via single-step assembly, and at a later time, self-destruct due to their packaged contents. These containers are spherical capsules formed by electrostatic complexation of the anionic biopolymer, gellan gum with the cationic biopolymer, chitosan. The capsules are termed "motherships", and are engineered to carry a payload of much smaller containers, i.e., nanoscale vesicles ("babyships"), within its lumen. By also packaging an enzyme, chitosanase, inside the capsule, we create "motherships" that self-destruct, releasing their payload of "babyships" in a pulsatile manner. The timescale for self-destruction can be engineered based on the internal concentration of enzyme. The "motherships" are stable when stored in a freeze-dried form and can be readily dispersed into buffer solutions at a later time, whereupon their "internal clock" for self-destruction is initiated. The above concept could be useful for the controlled release of a variety of payloads including drugs, biological therapeutics, cosmetics, or flavor ingredients.