Preparation And Application Of The Two Kinds Of Chitosan-based Antimicrobial Materials And One Kind Rhodamine-based Fe~Ⅲ Ion Probe

This dissertation consists of three parts:1. ReviewThis chapter describes the classified of antimicrobial agents and also describesadvantages and disadvantages of each kind of antimicrobial agents respectively. Weintroduced the natural organic polymer antibacterial agent of chitosan, itsmodification methods and application. At the same time, we expounded thesignificance of natural organic polymer/inorganic hybrid antibacterial material. So weestablished the researching object of synthetic organic polymer/inorganic hybridantibacterial material.The synthesis and application about rhodamine as fluorescent molecular probesare introduced. We expounded the significance of rhodamine as fluorescent molecularprobe. We composed one kind of fluorescent molecular probe using rhodamine6G forcellular Fe^Ⅲion detection.2. Synthesis and studying of two kinds chitosan-based natural organicpolymer/inorganic hybrid antibacterial materialThe novel material DTC （Dy2O3-TDI-CTS） was composed with toluene-2,4-diisocyanate （TDI） as the functional reagent, after a certain physical and chemicalapproach to dysprosium oxide nanoparticles and chitosan （CTS） grafted to TDI. Theminimal inhibitory concentration （MIC）, inhibition zone of the Staphylococcus aureusand Escherichia coli. was focused on. Meanwhile, its antibacterial activity wascompared with CTS. The results showed that the antibacterial activity of newsubstance was better than that of CTS. Resulted in increasing demand of dysprosiumoxide with the inhibition especially for Staphylococcus aureus, and expand the scopeof application of chitosan.A novel antibacterial material was prepared by chitosan （CTS） derivatives andsilver bromide nanoparticles using the method of on-site precipitation of AgBr. Thesynthesized composite were characterized by IR,1H NMR, TGA, SEM, EDS, XRDmethods. The material composed of a cationic polymer and silver bromide nanoparticles and has a good solubility in water. The antibacterial properties of thismaterial have been studied by the minimal inhibitory concentration （MIC） and theinhibition zone test. The antibacterial results showed that the material has highestactivity properties than the Silver （I） P-toluene sulfonate to the Staphylococcus aureusand Escherichia coli. Comparing with most silver-containing antimicrobial polymerswhich has a very low rate of dissolution in aqueous environment and some highlywater-soluble silver salts or silver（I） complexes，the synthesized material is soluble inwater and can provide a constant concentration of biocidal AgIions in aqueousenvironments.3. Synthesis and intracellular imaging applied of one kind rhodamine-basedfluorescent molecular Fe^ⅢprobeA higher selective and sensitive ion probe for the detection of Fe^Ⅲin aqueousmedia was made using Toluene2,4–diisocyanate （TDI） as a bridge to cuple Fe₃O₄nanoparticles（NPs） and Rhdomine6G hydrazide. The obvious color change of the ionprobe solution from colorless to pink upon the addition of Fe^Ⅲdemonstrated the ionprobe could be used for “naked-eye” detection of Fe^Ⅲin water at pH7. The highsensitivity for Fe^Ⅲwould be realized in neutral water with the detection limit down tothe1.5ppb level. The addition of1equivalent of each of these metal ions, includingMn^Ⅱ, Ni^Ⅱ, Y^Ⅱ, Eu^Ⅲ, Ce^Ⅲ, La^Ⅲ, Pr^Ⅲ, Cd^Ⅲ, Cr^Ⅲ, Sm^Ⅲ, FeⅡ, CuⅡand ZnⅡ, they did notbring any obvious fluorescence change. It confirmed the remarkable selectivity of theprobe for Fe^Ⅲ. And The fluorescence images of HeLa cells after incubation with Fe^Ⅲand then further incubated with the ion probe, leading to a strong intracellularfluorescence, which suggested the ion prober could penetrate the HeLa cell membraneand could respond to Fe^Ⅲin intracellular within living cells. Such a sensitive ionprobe for Fe^Ⅲ, would be important for studying behavior of intracellular iron.