The ability to prepare controlled-architecture, functional polymers is a significant advantage when trying to design new materials for applications in drug delivery, biological imaging, tissue engineering, etc. We explore routes to macromolecules that can be used in such applications because of the ability to self-assemble/dissociate in response to an applied stimulus. For instance, we prepare block copolymers that form micelles or vesicles when triggered by stimuli experienced in biological milieu. In some cases, these nanoassemblies are decorated with biological ligands that facilitate targeted delivery to tumors in order to localize the delivery of anticancer drugs. Systems with potential for delivery of other drugs have also been prepared by appropriately designing new responsive polymeric micelles and vesicles. For example, while the large majority of previous reports of stimuli-responsive block copolymers have involved well-known polymers with susceptibility to changes in temperature, pH, or ionic strength, we have helped expand the repertoire of applicable stimuli by preparing block copolymers that respond to changes in glucose concentration. These novel materials have potential therapeutic utility for the deliver of insulin during the treatment of diabetes.