الفهرس 
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Abstract
A new multifunctional magnato-plasmonicnancomposite(gold magneto Au-Fe3O4 hybrid nanostructure) has been developed to be used as a dual contrast agent for magnetic resonanceimaging(MRI) and computed tomography (CT). Gold magneto NPs were synthesized using the chemical co-precipitation method in presence of polyethylamine (PEI) asa capping agent and reducing agent for the gold. The produced nanoparticles have average size around 21 nm in diameteras determined from transmission electron microscopy.The optical and the magnetic properties had been investigated via absorption spectroscopy (UV-VIS) and vibrating sample magnetometer (VSM). The particles show characteristic absorption band due to surface plasmonresonance of the gold shelland a hysteresis loop due to the magnetic core. The crystal structure and chemical composition had been determined viaX-Ray diffraction (XRD), and the surface properties havebeen investigated using zeta potential. All the chemical analysis confirmedtheformationofthemono-dispersed core–shell Au-Fe3O4nanostructure. Thesenanoparticles were used as labeling material for bone marrow mesenchymal stem cells (BMSCs) in vitroand in vivo. Three different days of differentiation stem cells(day 0, day7 ,day21 HMSCs)were isolatedfrom bone marrow aspirates of human cultured and expanded, after which, they were incubated withgold magneto NPs.. In vitrovisibility thresholds were investigated by labelling MSCs with gold magnetoNPswitha concentration of50μg/ml and resuspending varying cell doses (16cells) to MR-imaging/CT. The effect of this labeling material in cell apoptosis as well asinautophagy were evaluated both by flow cytometry and acridine orange respectively.Annexin V/propidium iodidedouble staining for evaluation of apoptosis in the MSC labelled cells showed increase in the apoptotic figure from 16 to 26 % . Which was The results showedthat viability was unaffected in all of the cellsand MSCproliferation rates and differentiation potential revealed differencesbetween labeled and unlabeled MSCs.The geneexpressio pathway was also, investigated by apoptosis specific PCR array assay. we foundthattwenty sixout of the 84 studied genes weresignificantlydifferent expressed,are ranged from 4 to 10 fold changes. Only one showed down regul BCL2A1 and the other 25genes(AKT1,BCL2,BAG3BID,BIRC2,BIRC3,BNBRAF,CASP10,CASP2,.CASP7,CFLAR,CIDEA,CYCS,DFFA,DIABLO,IGF1R,0,LTA,NOD1,TNFRSF1A , TNFRSF 21 ,TP73 and XIAP) showedup regulation.