Synthesis And Application Of Fluorescent Hyperbranched Poly (Amido Amine)

Hyperbranched polymers have similar structures and properties of dendrimers, they have potential applications in various fields, such as drug delivery, catalysis and sensors. They can be easily prepared in comprison with dendrimers. Thus, the synthesis, characterization and properties of the hyperbrached polymer become one of the exciting research area of the polymers, and self-photoluminescence of the hyperbranched polymers have attracted more and more attentions in recent years. The main results obtained in this thesis are as follows:1. Disulfide-functionalized hyperbranched poly(amido amine)s (HPAMAMs) were synthesized by Michael addition polymerization of N,N'-cystaminebisacrylamide and 1-(2-aminoethyl)piperazine. The novel HPAMAMs displayed bright fluorescence, and the emissions bands cover nearly the whole visible wavelength range. When the polymer solutions were excited at 330–385, 460–490, and 510–550 nm, blue, green, and red solutions were observed, respectively. The HPAMAMs are biodegradable and they can be easily cleaved by 2-mercaptoethanol or glutathione, leading to a decrease in the fluorescence intensity.2. A water-soluble, biodegradable and fluorescent hyperbranched poly(amidoamine) with mannose groups on their surface (M-HPAMAM) has been successfully prepared, and the synthetic strategy includes Michael addition polymerization of diacrylamide with 1-(2-aminoethyl)piperazine and, subsequently, surface modification with mannosamine. The photoluminescence of M-HPAMAM was enhanced significantly due to the surface mannose groups. Incubation of E. coli with M-HPAMAMs yielded brightly fluorescent bacteria clusters, but the fluorescent intensity of the aqueous solution lowered. This indicates that the M-HPAMAMs have strong affinity with bacteria due to their polyvalent interactions. Based on the size and the amount of bacteria clusters formed, the bacteria with the concentrations higher than 102 cfu/mL can be detected.3. The tertiary amine, which was evidenced to be a fundamental chromophore, was successfully used in synthesis of fluorescent polymer nanoparticles (NPs) with surface galactosyl or glucose groups whilst its high fluorescence efficiency retained. The HPAMAM NPs were obtained from Michael addition dispersion polymerization of CBA, AEPZ and N-galactosamine hydrochloride (or N-glucosamine hydrochloride), and the resultant NPs displayed strong photoluminescence, high photostability, broad absorption and emission (from 430 to 620 nm) spectra. The results from incubation of the liver cancer cells, HepG2 with the gels showed that they are nontoxic, biocompatible, and can be recognized by asialoglycoprotein receptor on the surface of HepG2, and then be internalized.4. Hyperbranched poly(amido amine)s with glucose groups have been synthesized via the Michael addition polymerizations of triacrylamide with diacrylamide with 1-(2-aminoethyl)piperazine, subsequently, surface modification with glucosamine. When Fe³⁺ existed in aquesous solution, fluorescent intensity of the hyperbrached polymer decreased dramatically. This fluorescent poly(amido amine)s can be used as Fe³⁺ sensor.5. Electrospinning is a simple method to obtain polymer nanofibers. The electrospinning of hyperbranched poly(amido amine)s in methanol solution was performed and fluorescent nanofibers were obtained. The novel fluorescent nanofibers can be used as TNT sensors.