Self-aggregates mediated synthesis of stimuli-responsive nanogels and their applications

Abstract

Cross-linked gel-like nanoparticles, nanogels, have received great interests as drug carriers because they possess structural stability, stimuli-responsivity, high drug loading capacity, and many others. There have been the numbers of attempts to prepare chemically cross-linked nanogels. The water-in-oil heterogeneous miniemulsion stabilized by surfactants was frequently utilized as templates, and the monomers could be pol-ymerized with bifunctional monomers in the aqueous droplets. Despite this success, a simple chemistry of nanogel preparation with echo-friend, high throughput, and surfactant, emulsion and expensive coupling agents free became desirable in practical point. Furthermore, the analysis of swelling behavior of nanogels would a worthwhile subject to investigate. Nanogels have high mechanical stability due to chemical cross-linking, thereby helping nanogels to entrap drugs stably in systemic circulation. Accordingly, nanogels can reduce side effects originated from the prema-ture drug release. To improve drug efficacy, however, nanogels should be able to release drugs in target site. In this study, diverse morphological nanogels such as cross-linked micelles, cross-linked vesicles and hy-drogel nanoparticles were prepared by self-aggregate mediated synthesis. And disulfide cross-linked nanostructures investigated for intracellular triggered drug release for anticancer drug delivery. In chapter 2, the focus of the research was on the design and synthesis of new type of cross-linkable am-phiphilic copolymer to prepare core cross-linked micelles and vesicles. Poly(succinimide-b-ethylene glycol) (PEG-b-PSI) were synthesized as amphiphilic polymer. The spherical and vesicular self-aggregates were pre-pared by controlling the hydrophilic/hydrophobic ratio. The poly(succinimide) core could be cross-linked by diamine cross-linkers, and the morphologies of aggregates were fixed. The cross-linked nanostructures showed a high structural stability, and they ha...