Development of Responsive Nano/Microgels for Materials Application
Year of Dissertation:
Abstract Development of Responsive Nano/Microgels for Materials Application By Ting Zhou Adviser: Professor Shuiqin Zhou Stimulus-responsive polymer microgels swell and shrink reversibly upon exposure to various environmental stimuli such as change in pH, temperature, ionic strength or magnetic fields. Therefore, they become ideal candidates for biomaterial applications. This work covers the general areas of responsive microgels and their application on controlled and targeted drug release. According to the therapy purpose, this work can be classified to two parts. The first part of this thesis (chapter 3-5) focused on the development of biocompatible microgels-based drug delivery systems as anticancer drug carrier. These microgels are constructed from thermo-responsive and/or pH-responsive biocompatible materials, such as, oligo(ethylene glycol) and chitosan. The effects of pH values and temperatures on drug release behaviors of these stimulus-responsive microgels have been discussed. In chapter 5, hybrid ZnO quantum dots (QDs) encapsulated pH and temperature dual-responsive core-shell structure microgels has been prepared, which can not only be applied as targeting drug release system, but also can act as optical sensor for imaging in therapeutic application. The latter part of this thesis (chapter 6, 7) investigated the synthesis, functionalization and characterization of glucose-responsive microgels for diabetes therapy purpose. CdS QDs immobilized glucose-sensitive microgels exhibit fluorescence quenching in the physiologically important glucose concentration range 1-25 mM, which shows promise for a continuous non-invasive in vivo glucose sensing system. In another chapter, core-shell microgels with the P(NIPAM-AAm-PBA) microgel as core and the P(MEO5MA) gel layer as shell were prepared for biocompatibility purpose. The presence of P(MEO5MA) shell could prevent the glucose-sensitive core network from swelling due the hydrogen bonding between oxygens from P(MEO5MA) side chains and glucose molecules, resulting in a shift of glucose sensitivity of core-shell microgels to higher glucose concentration in comparison with the free parent core microgels. Therefore, the set point of glucose sensitivity of microgels could be adjusted possibly and result in potential biomedical applications.