Preparation And Characterization Of Amino Polyelectrolyte Composite Nanoparticles

Nano-biotechnology is the interdisciplinary field of nanotechnology and bio-technology, that is, to manufacture the nano-scale devices through simulation or biological systems, or to research and change the structure and properties of organisms by using micro-devices at nano-scale. Polymer nanoparticles have large specific surface areas, easy separation, ability of anchoring with various functional groups, good separation, biocompatibility and lots of other advantages, inorganic nanoparticles, such as metals and semiconductors, have unique properties. So the functional polymer composite microspheres have large potential in biomedical field such as medical delivery, bio-separation, bio- label, therapeutic, and bio-catalysis.This paper is based on the amino polyelectrilyte, focus on the self-assembly of the copolymer (h-PAMAM-g-PEG) and the composition and assembly between the polyelectrilyte and inotganic nanoparticles, discussed the formation of the assembly and the composite microspheres. The results can be divided into three parts as follows:(1) In the second chapter, we synthesized hydrophilic polyelectrolyte copolymer PEG grafted hyperbranched polyamidoamine (h-PAMAM-g-PEG) with different PEG graft density, the copolymer was micellization in selective solvent (THF). Hollow/Solid microspheres were obtained when the micelle was crosslinked with 1,6-dibromohexane in THF and transferred into water phase. The grafting density of PEG will impact the dimension, the formation time, and the morphology transformation of the micelle. Meanwhile,h-PAMAM had pH dependent fluorescent characteristic which do not change with the self-assemble and phase transition. Above all, we get a polyelectrolyte microspheres with stable, regular shape, biological compatibility and fluorescent properties.(2) In the third chapter, continue to use the polyelectrolyte h-PAMAM-g-PEG prepared ahead. Acid-sensitive cis-aconityl linkage was introduced between DOX and h-PAMAM-g-PEG to produce PPCD conjugates. Drug-loaded polymer microspheres were obtained when the self-assembly micelle was crosslinked in THF and transferred into water phase, the loading rate of adriamycin(DOX) was 12.4%. Since there is a large number of amine on the h-PAMAM-g-PEG, positive microspheres was obtained after the assembly. The drug-loaded microspheres possessed the pH sensitivity, all of these will promote the application of drug-loaded polymeric microspheres (PPCD) as tumor targeting drug carrier.(3) In the chapter four, we prepared gold nanoparticles by the method sodium citrate reduction,and stable CdTe fluorescence quantum dots were prepared by hydrothermal method. Through the electrostatic interaction between the amino groups of polyelectrolyte and carboxyl groups of inorganic nanoparticles, we studied the electrostatic assembly behavior of AuNPs/PLL, QDs/PLL and QDs/CS respective. The morphology of composite assembly can be controlled by changing the type of the Nanoparticles, and the molar ratio of the polyelectrolyte and the nanoparticles. In addition, EDC/NHS was introduced by activating the surface carboxyl of the quantum dots, the amidation occurred between the amino groups of the polyelectrolyte PLL or h-PAMAM-g-PEG and the carboxyl group to formed composite assembly. What’s more, both quantum dots and phthalocyanine was grafted on h-PAMAM-g-PEG to obtain the linear network structure. It showed that we formed stabile polyelectrolyte assembly remained the characteristic of the inorganic nanoparticles.