Investigation And Application Of Supermolecule Functionalized Magnetic Nanoparticles

Chapter 1: The structure,properties,preparation,functionalion of Fe₃O₄ magnetic nanoparticles and the application progress of Fe₃O₄ magnetic nanocomposites in details have been briefly reviewed in this chapter.Chapter 2: The triformylcholic acid modified magnetic nanoparticles TCA-MNPs have been prepared via layer-by-layer method.The structure,particle size,morphology and magnetic properties of TCA-MNPs were characterized by Fourier transform infrared spectroscopy?FTIR?,transmission electron microscopy?TEM?,X-ray diffraction,magnetic properties analysis and thermogravimetric analysis?TGA?.The results of FTIR spectroscopy demonstrated that triformyl cholic acid has been successfully modified onto MNPs,and the grafted amount of the triformyl cholic acid was 36.75 mg/g calculated by TGA experiment data.The MNPs and TCA-MNPs dispersed uniformly at 10 ± 2 nm observed from TEM micrographs which were consistent with the particle size of TCA-MNPs was 10.20 nm calculated by X-ray diffraction experiment.The hysteresis loops indicate that TCA-MNPs have superparamagnetism and saturation magnetization values was 57 emu/g.Chapter 3: Using TCA-MNPs as drug carrier,whereas DOX and EPI as model drugs,the loading and release behaviors for TCA-MNPs by fluorescent spectrometry methods.The loading amount was closely related to the initial drug concentration and drug loading time.Under appropriate conditions,the drug loading for DOX and EPI can reach up to1363.6 mg/g and 1293.5 mg/g,respectively.The drug release experiment displayed that the release efficiency was pH-sensitive.At pH5,the cumulative release rates of DOX and EPI in 6 hours reached to 42.2% and 44.5%,respectively.The MTT assays showed that TCA-MNPs had no obvious cytotoxicity for HepG2 and K150 cells,while DOX and EPI loaded TCA-MNPs exhibited high potency to kill HepG2 cells than K150 cells.In addition,cell imaging experiments and flow cytometry testified that both the TCA-MNPs@DOX and TCA-MNPs@EPI could enter the cell and releasing the drug.Moreover,the drug-nanocomposits were more likely to enter the HepG2 cells than K150 cells,suggesting that the cholic acid modified MNPs was a liver targeted drug carriers for biomedical applications.Chapter 4: The Formyl deoxycholic acid and Formyl chenodeoxycholic acid modified magnetic nanocomposites FDCA-MNPs and FCDCA-MNPs were synthesized via layer-by-layer method.The structure,particle size,morphology and magnetic properties of FDCA-MNPs and FCDCA-MNPs were characterized by Fourier transform infrared spectroscopy,transmission electron microscopy,X-ray diffraction,magnetic properties analysis and thermogravimetric analysis.The results of Fourier transform infrared spectroscopy demonstrated that triformyl deoxycholic acid and triformyl chenodeoxycholic acid were successfully modified to MNPs,and it was further calculated that the modified amount of the triformyl deoxycholic acid and triformyl chenodeoxycholic acid were 32.12 mg/g and 34.75 mg/g by thermogravimetric experiment.The MNPs and TCA-MNPs dispersed uniformly at 10 ± 2 nm observed from TEM micrographs which were consistent with the particle size of TCA-MNPs were 10.12 nm and 10.00 nm calculated by X-ray diffraction experiment.The hysteresis loops indicate that both FDCA-MNPs and FCDCA-MNPs have superparamagnetism and saturation magnetization values were 60 emu/g and 58emu/g,respectively.Chapter 5: The proposed magnetic nano-drug carrier FCDCA-MNPs was used to load OTC and CTC.The maximum loading capability of FCDCA-MNPs for OTC and CTC were 59.65 mg/g and 64.56 mg/g,respectively.Meanwhile,the release behavior of drugs demonstrated that the FCDCA-MNPs were pH-dependent,which exhibited faster release properties in alkaline solution than in neutral environments.Based on the antimicrobial experiment in vitro,the synergetic sterilization of FCDCA-MNPs@OTC and FCDCA-MNPs@CTC can effectively inhibite the bacterial growth,which is more preferential than the OTC and CTC,and the FCDCA-MNPs have no ability of killing bacteria.It is indicated that the antibiotics-nanocomposits can effectively reduce the using amount of antibiotics.Chapter 6: Carboxymethyl-b-cyclodextrin polymer modified magnetic nanoparticles CDP-MNPs were prepared with a one-step method by anchoring cyclodextrin polymer onto the surface of Fe₃O₄ superparamagnetic nanoparticles?MNPs?.The loading and release behaviors of CDP-MNPs as drug carrier were evaluated by fluorescence spectroscopy method using camptothecin?CPT?as model drugs.The pH effects on CDP-MNPs for drug releasing were investigated.Under the optimum p H conditions,the maximum loading quantities of CDP-MNPs for CPT was 149 mg/g,and the loading behavior followed Freundlich adsorption balance equations with multilayer adsorption.Furthermore,the release ability of CDP-MNPs@CPT compounds was more efficient under natural solution than acid solution at 37 ? in vitro.Accumulated release efficiency of CPT in 6 h was 37.4 % at pH 7.4.In addition,the MTT assays showed CDP-MNPs had excellent biocompatibility,and the CDP-MNPs@CPT decreased the relative cellular viability of HepG2 cells evidently.