hyperbranched inorganic nanocrystals in polymer preparation and assembly of application

　　Title: hyperbranched inorganic nanocrystals in polymer preparation and assembly of application
　　Author: Shi Yunfeng
　　Degree-granting units: Shanghai Jiao Tong University
　　Keywords: Hyperbranched polyamidoamine;; nanoreactor;; CdS quantum dots;; Au nanocrystals;; single molecule micelles;; two-phase system;; Ag nanocrystals;; supramolecular self-assembly;; hyperbranched poly ethylene imine;; magnetic Rare earth magnets nanocrystals;; magnetic non-viral gene vector;; magnetic transfection; Amphiphilic hyperbranched polyamidoamine;; CdTe nanocrystals;; interface assembly
　　Abstract:
　　Hyperbranched polymers are a class of quasi-spherical structure of highly branched macromolecules with a large number of terminal functional groups and internal cavities. Hyperbranched polymer structure is unique, simple preparation, so increasing attention has been paid. Today, the hyperbranched polymer synthesis, characterization, functional modification technology has matured and improved, the application of hyperbranched polymers gradually rise. People in the self-assembly of hyperbranched polymers, controlled drug release, nano-encapsulation, gene transfer and many other areas of extensive research, but the hyperbranched polymers have some applications to be developed and improved. This consolidated previous work on hyperbranched polymers on the basis of the functional hyperbranched polymers has made some new exploration and research. Functional groups based on the Task Force on Non-active monomers for synthesis of hyperbranched polymers strategy, we prepared a hyperbranched polyamidoamine (HPAMAM), then HPAMAM chemical modification or by non-covalent interactions to build different types of Nano-reactor and for the preparation of CdS quantum dots and Au, Ag and other metal nanocrystals; use of hyperbranched polyethylenimine (HPEI), we prepared in situ organic - inorganic hybrid magnetic non-viral gene vectors, and study its magnetic properties of http://www.chinamagnets.biz/ transfection; Palm chloride we synthesized capped amphiphilic hyperbranched polyamidoamine (HPAMAM-PC), and studied HPAMAM-PC on the CdTe and Au nanocrystals package performance, respectively, to achieve the CdTe and Au nano- crystals in water / chloroform interface of self-assembly. Specific research content and main conclusions are summarized as follows:
　　1 to hyperbranched polymers as nano-reactor preparation of inorganic nanocrystals
　　Synthesis of ester end groups of hyperbranched polyamidoamine, and its reactor was prepared as a nano-particle size small and uniform size distribution of CdS quantum dots. We examined the Cd2 + / S2-molar ratio, reaction temperature, pH and aging time on CdS quantum dot optical properties, and with UV-Vis, PL, TEM and FT-IR, etc. on the prepared nanocomposite were characterized.
　　2 to amphiphilic hyperbranched polymers as single-molecule nano-reactor system in the two-phase preparation of inorganic nanocrystals
　　Developed a system using two-phase monodisperse, uniform size distribution of CdS quantum dots of the new method. In the two-phase system, chloroform and water, respectively, as cetyl chloride-terminated hyperbranched polyamidoamine (HPAMAM-PC) and Cd (CH3COO) 2/Na2S solvent. HPAMAM-PC has a hydrophilic hyperbranched polyamidoamine core and hydrophobic hexadecyl arm, chloroform and other solvents in the formation of a single molecule micelles. As a single molecule micelles as nano-reactor package Cd2 +, and further reaction with the S2-get size of CdS quantum dots uniform. We also successfully extended to the preparation method of diameter less than 2 nm Au, Ag and other metal nanocrystals.
　　3. Supramolecular self-assembly of nano-reactor Preparation of CdS quantum dots and its behavior
　　Proposed a self-assembly using supramolecular nano-reactor to Prepare CdS quantum dots of the new strategy. Self-assembled nano-reactor by palmitic acid and amino end groups of hyperbranched polymers by electrostatic interactions and ion-pair constructed. In the water-oil two-phase system, the water phase of Cd2 + in chloroform and transferred to the first phase of spontaneous self-assembly of nano-reactor, with the water phase of the S2-reaction, to generate light yellow chloroform solution of CdS quantum dots . By adding triethylamine, self-assembled nano-reactor preparation of CdS quantum dots from the chloroform phase transferred to the water phase. After dialysis and drying rotary evaporation, CdS quantum dots again dissolved in chloroform solution containing the palmitic acid in order to achieve a CdS quantum dots in water and oil transfer between two phases.
　　4. The use of hyperbranched polymers in situ preparation of magnetic non-viral gene transfection vectors and magnetic properties of
　　To achieve an in situ preparation of organic - inorganic hybrid magnetic non-viral gene vectors of the new route. Organic - inorganic hybrid magnetic non-viral gene vector in different divalent iron salts and molecular weight of hyperbranched polyethylenimine (HPEI) in the presence of prepared. HPEI is the ideal non-viral gene carriers, in this article it is not only used as nano-reactor and stabilizer to synthesize magnetic nanocrystals, and is cleverly used in place of our alkali metal hydroxide and ammonia as the reaction to provide the required base. By adjusting the HPEI/FeSO4 · 7H2O (w / w) and change HPEI molecular weight, content and preparation of the different magnetic saturation magnetization of the magnetic non-viral gene vector. MTT assessment show that the magnetic non-viral gene vector toxicity than the corresponding HPEI of toxicity. We further studied the magnetic non-viral gene transfection vectors of the magnetic properties, the study found luciferase in COS-7 cells the expression of the highest standard transfection can be achieved HPEI 13 times.
　　5 using amphiphilic hyperbranched inorganic nanocrystals in polymer to achieve the two-phase oil-water interface assembly
　　Established a core-shell using amphiphilic hyperbranched polymers to achieve CdTe and Au nanocrystals in water / oil interface is assembled in new ways. The CdTe nanocrystals, for example, CdTe nanocrystals was first transferred to chloride end-capped with hexadecyl hyperbranched polyamidoamine (HPAMAM-PC) in chloroform solution, by lowering the pH of the aqueous phase or water phase into α-cyclodextrin (α-CD), CdTe nanocrystals will be in the water / chloroform interface of self-assembly. We get the CdTe / HPAMAM-PC self-assembled membrane fluorescence microscope, UV-Vis, PL, TEM, EDS, FT-IR, DSC and TGA were characterized.
　　In summary, this paper based on chemical modification of hyperbranched polyamidoamine or non-covalent interactions to build different types of nano-reactor and for the synthesis of CdS quantum dots and Au nanocrystals; use of hyperbranched polyethylenimine original bit magnetic nanocrystals prepared packages of organic - inorganic hybrid non-viral gene vectors, and studied the magnetic properties of transfection; We also use amphiphilic hyperbranched polyamidoamine were encapsulated CdTe and Au nano-crystals, and were achieved the CdTe and Au nanocrystals in water / chloroform interface of self-assembly. In short, we prepared a series of inorganic crystal / hyperbranched polymer nano-hybrid materials, hyperbranched polymers and for the practical application of nanocrystals provide important information.
　　Degree Year: 2010