Preparation Of Fluoresent Polymer Films And Fluoresent Polymer Micelles Used As Drug Carriers

Fluorescent polymer is a kind of luminescent materials, which can emit light after the absorption of light or other electromagnetic radiation. According to the different synthesis methods, fluorescent polymer can be divided into two categories:doped fluorescent polymer and chemical bonded fluorescent polymer. Compared with doped fluorescent polymer, the chemical bonded fluorescent polymer is more widely used, various and stable of fluorescent properties. As excellent chromophore, perylene derivatives possess outstanding optical, thermal and chemical stability and high fluorescence quantum yield. In particular, the strong absorption and fluorescent emission in visible region. The fluorescent polymer, in which perylene derivatives used as the fluorescence chromophore and named as perylene fluorescent polymer, can inherit the fluorescence properties of perylene derivatives and possess some unique properties of polymers, such as easy synthesis and film forming. Polyphosphoesters are biocompatible and biodegradable. Due to the existence of pentavalent phosphorus atom in the backbone chain, the structure of polyphosphoesters is various, easy to modify and function, as a consequence, their physical and chemical properties are easy to adjust. Therefore, Polyphosphoesters can be used as a drug carrier, gene carriers, and tissue scaffold, and have been widely applied in biomedical field. The research contents of this paper is the preparation of the perylene fluorescent polymer, by grafting perylene derivatives in the side chain and perylene derivatives used as initiator:polyvinylpyrrolidone (PVP)-based perylene fluorescent polymer films and perylene derivatives cored block copolymers, as well as, the fluorescent copolymers as a drug carrier used in cancer treatment. The research contents and results of this paper can be divided into the following several aspects:1. A PVP-based fluorescent film with perylene-assembled nanostructures was prepared at certain temperature and pressure by using 3,4,9,10-perylenetetracarboxylic acid dianhydride (PDA) as the chromophore. The reaction mechanism is as follows:linear PVP ring-opened and self-crosslinked to form PVP network, and the PDA π-conjugated structures were intertwined by PVP to form rod-like structures; PDA π-conjugated structures were incorporated into the film via covalent bonds between the anhydride and ring-opened PVP, and the stable fluorescent film was formed. The reactive group of anhydride in perylene is essential for the preparation of the stable fluorescent film. Scanning electron microscopy (SEM) images show that the surface of film was composed of many rod-like structures. High resolution transmission electron microscopy (HRTEM), polarized optical microscopy (POM) and X-ray diffraction (XRD) demonstrated the rod-like structures are PDA π-conjugated structures.2. A PVP-based fluorescent film was prepared at certain temperature and pressure by using 4C1-PDI as the fluorophore. The reaction mechanism is as follows:linear PVP ring-opened and self-crosslinked to form PVP network, and the 4C1-PDI molecules were intertwined by PVP to form microspheres; 4C1-PDI molecules were incorporated into the film via covalent bonds between the chlorine atoms and the amine groups of ring-opened PVP, and the stable fluorescent film was formed. The reactive group of chlorine atoms in perylene is essential for the preparation of the stable fluorescent film. Scanning electron microscopy (SEM) images show that the surface of film was composed of many microspheres. XRD demonstrated the 4C1-PDI dye appeared as amorphous in the film.3. By introducing hydroxyl functional groups in the bay position, a initiator with eight arms was synthesized.4C1-PDI, which has been produced previously in our laboratory, was used as the raw material. The initiator with eight arms (80H-PDI) was synthesized via nucleophilic substitution, esterification and deprotection. The 8OH-PDI was used as initiator, triggering the ring-opening polymerization of lactide or polyphosphoesters monomers, and two eight-arms fluorescent block copolymers were prepared. The amphiphilic copolymers can self-assemble into supramolecular micelles in aqueous solution. We used nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) to characterize the two block copolymers. The morphology and size of the micelles were also characterized.4. Fluorescent copolymers PDI-star-(PLA-b-PEEP)8 was used as drug carriers for the treatment of cancer. PDI-star-(PLA-b-PEEP)8 possess good fluorescence properties in in aqueous solution, which is benefit for bioimaging. The camptothecin can be efficiently loaded in PDI-star-(PLA-b-PEEP)8 micelles through hydrophobic interactions. Cell toxicity tests show that PDI-star-(PLA-b-PEEP)8 micelles has good biocompatibility. Confocal laser scanning microscopy and flow cytometry analysis showed that the micelles are easily cell uptaked and internalized by cancer cells. In vitro cell toxicity tests show that the cytotoxicities of camptothecin-loaded micelles are significantly higher than those of free camptothecin. In vivo tumor inhibition test, the camptothecin-loaded micelles prefer to accumulate at the tumor site via enhanced permeability and retention (EPR) effect, thus the average tumor inhibition rate of camptothecin-loaded micelles was greatly higher than that of free CPT.