Biological Characteristics Research Of Galactose Functionlized Thermoresponsive Double-hydrophilic Copolymer Micells

In recent years, according to the controllable morphologies, adjustable response temperature and excellent biocompatibility, thermoresponsive double-hydrophilic polymeric micelles as novel functional polymer materials have attracted growing attentions in biomedical material field. Meanwhile, the adding of glycosyl can improve the polymer hydrophilia and reduce the cytotoxicity, so the synthesis and application of glycosyl-based functional polymeric materials have been favored all over the world.Based on the much research of predecessors, a series of novel thermoresponsive glycopolymers based on different thermoresponsive monomers were designed and synthesized via reversible addition-fragmentation chain transfer(RAFT) polymerization. The chemical constitutions of them were confirmed by nuclear magnetic resonance spectroscopy(1H NMR), Fourier transform infrared spectroscopy(FTIR) and gel permeation chromatography(GPC), the thermoresponsive glycopolymer micelles were obtained using self-assembly technology. Their thermoresponsive properties, biocompatibility and protein specific recognition capacity were investigated systematically.Chapter 1 presented a detailed review of synthesis and application progress of PDEGMA-based thermoresponsive polymer, galactose glycopolymers, and the research background of the structure and properties of lectin.Chapter 2 presented the synthesis of thermoresponsive glycopolymers based on different thermoresponsive monomers by a combination of enzymatic synthesis and reversible addition-fragment chain transfer(RAFT) polymerization protocols, and the characterization of chemical constitution using different technical methods. In order to achieve both bioactivity and thermoresponsibility, three sugar-functionalized monomers 6-O-vinylsuccinioyl-D-galactose(OVSG), 6-O-vinyladipoyl-D-galactose(OVNG), 6-O-vinylazelaioyl-D-galactose(OVZG) prepared by enzymatic synthesis and thermoresponsive monomers diethyleneglycol methacrylate(DEGMA) were used to obtain a serials of novel thermoresponsive glycopolymers with different linkers of carbon numbers such as poly(diethyleneglycol methacrylate)-b-poly(6-Ovinylsuccinioyl-D-galactose) PDEGMA-b-POVSG, poly(diethyleneglycol methacrylate)-b-poly(6-O-vinyladipoyl-D-galactose) PDEGMA-b-POVNG, poly(diethyleneglycol methacrylate)-b-poly(6-O-vinylazelaioyl-D-galactose) PDEGMA-b-POVZG, poly(diethyleneglycol meth- acrylate-co-6-O-vinyladipoyl-D-galactose) P(DEGMA-co-OVNG) and via RAFT polymerize- tion. All the precisely synthesized glycopolymers were characterized by 1H NMR, FTIR and GPC. The results showed that the molar ratios of monomer in the resultant glycopolymers were basically consistent with the feed of the monomer ratios; well-defined block glycopolymers with arrow polydispersity(PDI was about 1.5) were prepared via RAFT polymerization; the linear dependence of number-average molecular weight(Mn) of PDEGMA with the conversion percentage was found, which indicated RAFT polymerization was controllable.Chapter 3, based on the research of chapter 2, presented the fabrication of thermoresponsive glycopolymer micelles by self-assembling, and revealed the thermoresponsibility and self-assembly mechanism of glycopolymers with different structures. The lower critical solution temperature(LCST) of thermoresponsive glycopolymers was studied using UV-visible spectrophotometer(UV-vis), the LCST values of block glycopolymer PDEGMA-b-POVSG was above 45 oC, the LCST values of block glycopolymer PDEGMA-b-POVNG were 32, 37, 40 oC, the LCST values of block glycopolymer PDEGMA-b-POVZG were 29 oC, the LCST values of random glycopolymer P(DEGMA-co-OVNG) were 38, 36 oC. Overall, the LCST values of glycopolymers decrease with increasing carbon numbers of galactose monomers in the glycopolymers. To obtain average hydrodynamic radius(Rh) and average gyration radius(Rg) at different temperature, the Laser light scattering(LLS) was used combined static laser scattering(SLS) and dynamic laser scattering(DLS). Rh and Rg of thermoresponsive glycopolymer micelles were depended on the temperature, and the coil-globule transition also was revealed. Micelle morphology of the block glycopolymers was investigated by transmission electron microscopy(TEM), which showed self-assembled micelles with uniform sizes and a regularly spherical shape. The result revealed that thermoresponsive glycopolymers prepared by RAFT polymerization were able to self-assemble into globose nano-micelles, and the LCST values of glycopolymers could be adjusted precisely. According to this study, biomedical polymer system and application of glycopolymers were enriched.In the chapter 4, we aimed at thermoresponsive glycopolymer micelles fabricated by self-assembling to study the structure effect on protein recognition capacity, the temperature influence on protein recognition capacity, the ability of targeted combination between micelles and two different kinds of cells, and the changes of cellular apoptosis were induced by micelles recognized with two lectins. The results indicated that the sugar moieties in glycopolymers were more and the recognizability to protein was greater; the structure was more regular and the recognizability to protein was greater; the temperature was lower and the random coil structure of glycopolymer micelles were more flexible to bind lectin, and more sugar moieties were exposed to bind lectin; the glycopolymer micelle solutions had generally very good biocompatibility, and RCA120 or PNA-loaded micelle solution were able to promote cancer cell death. These results make this study more valuable in the application of protein recognition and drug delivery systems.In the chapter 5, we summaried the main content in this study, and also look into the future in this field.