| Chapter 1:This chapter briefly introduced the structure,properties,preparation and functionalization of magnetic Fe3O4 nanoparticles,and the research progress in applications of functionalized magnetic Fe3O4 nanocomposites were reviewed in details.Chapter 2:Magnetic nanoparticles Fe3O4 functionalized graphene oxide?MGO?was prepared by co-precipitation and?-cyclodextrin??-CD?was grafted on the surface via a layer-by-layer-assembly method.The?-CD modified magnetic graphene oxide?MGO-CD?was characterized by TEM and AFM,etc.MGO-CD was used to modify glassy carbon electrode?GCE?for determining tryptophan.Fe3O4 could enhance the electrical conduction and?-CD showed excellent inclusion ability,which were confirmed by cyclic voltammetry and electrochemical impedance.Then the amount of modified MGO-CD,pH of the electrolyte,scanning speed and reacting time were optimized.Under the optimal conditions,the oxidation peak current showed a calibration response for tryptophan over a wide linear range from 5.0×10-7 to 7.5×10-4 M with a detection limit of 3.1×10-7 M?S/N = 3?.The method demonstrated excellent selectivity,repeatability and stability,which had been successfully applied to the determination of tryptophan in amino acid injection,and satisfactory results were obtained.Chapter 3:Different proportions of MGO-CD nanocomposites were synthesized by adjusting the weight ratio,which were characterized by FTIR,TGA and VSM.Doxorubicin hydrochloride?DOX?and epirubicin hydrochloride?EPI?as model drugs were loaded onto the MGO-CD.The loading amount was detected by UV-Vis spectrum,which exhibited that MGO-CD possessed remarkably higher loading capacity for DOX?909.09 mg/g?and EPI?781.25 mg/g?than MGO.The absorption model was fit for multilayer Freundlich model.The release profiles of the drugs were investigated by fluorescent spectrometry,which were pH-sensitive due to the exist of hydrogen bond,and the highest release were obtained at pH 5.3.Furthermore,the fluorescence images demonstrated that MGO-CD/DOX displayed a more excellent delivery and superior release than MGO-CD/EPI.The MTT assays showed that pure MGO-CD had no obvious cytotoxicity?>90%cell viability?while drug loaded MGO-CD?<30%?revealed significantly high potency to kill MCF-7 cells,suggesting that multi-functionalized MGO-CD was an efficient nanoplatform for targeted delivery and controlled release of anticancer drugs for biomedical applications.Chapter 4:The ?-cyclodextrin assemblied magnetic Fe3O4 nanoparticles??-CD-MNPs?were successfully fabricated via a layer-by-layer method,which were characterized by TEM,FTIR,element analysis and NMR,etc.The resultants possessed good stability and super-paramagnetic response?Ms 64 emu/g?.Stereoisomeric DOX and EPI were used as model drugs to investigate the loading and release behaviors by fluorescent spectrometry.The ?-CD-MNPs showed a high loading capability of 72.48 and 39.46 mg/g for DOX and EPI,which were fit for Freundlich model.The release was pH-responsive,and at pH 5.3 reached the highest.1H NMR confirmed that partial anthracene ring of drug molecule was included by(3-CD,and the computer simulation gave the further evidence.In addition,the MTT assays showed(3-CD-MNPs had excellent biocompatibility on MCF-7 cells.Cellular imaging indicated that different amounts of DOX or EPI could be transported to the targeted site and released from the internalized carriers.The results demonstrated that(3-CD-MNPs could be a very promising vehicle for delivery of DOX and EPI.Chapter 5:This part summarized the MGO-CD modified GCE for electrochemical detection of tryptophan,and the loading and release behaviours of MGO-CD and ?-CD-MNPs nanocomposites for stereoisomeric anti-cancer drugs,DOX and EPI.The new methods of preparing functionalized magnetic nanosystems would be established and they were expected to be applied in many other fields. |
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