Preparation And Properties Of Functional Fluorine-containing Polymer Microspheres

Recently, the research on polymer microspheres is developing very rapidly. Due to the special size and morphology, the polymer microspheres have been applied in every field. In particular, the application for polymer microspheres as the drug delivery carrier attracts much attention, because of the increasing demand for the high quality of medical treatment. More importantly, the drug-loaded microspheres have many advantages, such as the long drug half-life, the protection for the activity of drug, and the targeting of drug therapy. In this work, two kinds of novel functional polymer microspheres, temperature-responsive fluorinated self-assembled micelles and pH-responsive fluorine-containing microgels, were studied in detail.In selective solvent, amphiphilic graft copolymers can undergo a process of micro-phase separation, and self-assemble into micelles with regular structure. In our study, novel temperature-responsive fluorinated amphiphilic grafted copolymers were synthesized via the "grafting through" method. The lower critical solution temperature (LCST) was38.9℃, which was higher than the body’s normal physiological temperature. In aqueous solution, the grafted copolymers could self-assemble to form micellar system with core-shell structure. It was noteworthy that the polymer micelles displayed a significant temperature-responsive behavior. The study indicated that the fluorine-containing thermo-sensitive copolymer microgels had promising potential applications as a "smart" drug carrier in biomedical field.Microgels are a kind of intramolecularly highly cross-linked polymer colloidal particles, and have a unique swelling/collapse property. In our study, a pH-responsive fluorinated polymer microgel was prepared via soap-free emulsion polymerization. The pH-responsive behavior of microgels were studied by the fluorescent probe technique, dynamic light scattering and Zeta potential analysis, and then the drug loading capacity and controlled release were investigated using5-FU as a drug model. The results showed that the microgels underwent a swelling/collapse process with the change of pH values, and the drug release profile displayed an obvious pH-responsive characteristic. Our study suggests that the polymer microgels can achieve targeting drug release in lesion site by the stimulus of pH.