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  • Küçük Resim
    Öğe
    Characterization of magnetic Fe3O4@SiO(2)nanoparticles with fluorescent properties for potential multipurpose imaging and theranostic applications
    (Springer, 2020) Kurnaz Yetim, Nurdan; Kursun Baysak, Fatma; Koc, Mumin Mehmet; Nartop, Dilek
    Fe(3)O(4)magnetic nanoparticles (MNPs) were produced using hydrothermal synthesis and coated with tetraethyl orthosilicate (TEOS) where Fe3O4@SiO(2)MNPs with fluorescent properties were obtained. Structural characterization of the nanoparticles was performed using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Structural investigations confirmed that nanoparticles were in core@shell form. Chemical characterizations were performed using Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. Chemical investigations confirm that TEOS coating was successfully formed SiO(2)shells on Fe(3)O(4)nanoparticles. Magnetic characterizations revealed that nanoparticles show superparamagnetic properties which make them a suitable candidate for magnetic hyperthermia and magnetic resonance imaging (MRI) applications. Increased thickness of SiO(2)shell in nanoparticle structure results in decreased magnetic saturation values. Fluorescence properties of the nanoparticles were confirmed using fluorescence spectroscopy. Increased SiO(2)shell thickness results in increased fluorescent intensity. It was confirmed that Fe3O4@SiO(2)nanoparticle has the potential to be used in medical applications such as MRI, fluorescence imaging and magnetic hyperthermia, and so on.
  • Küçük Resim
    Öğe
    Ensuring traceability of organophosphate pesticides (OPs) through enzyme immobilized spheres
    (Springer, 2021) Hasanoglu ozkan, Elvan; Kurnaz Yetim, Nurdan; Nartop, Dilek; Sari, Nursen
    Currently, pesticide residues increasingly lead to health problems. Acetylcholinesterase enzyme (AChE) plays a role in detoxification processes due to their ability to scavenge organophosphates. Thus, this enzyme has been selected for the detection of pesticides. Herein, this study describes the preparation and application of appropriate new immobilized spheres that could be used for the detection of organophosphorus pesticide residues. That is a simple colorimetric enzymatic assay for the practical discovery of N-(Mercaptomethyl) phthalimide S-(O, O-dimethylphosphorodithioate) from organophosphorus pesticides (OPs) widely used in the treatment of sugar beet, apple, nut, corn, and tobacco. The process is based on the immobilization of acetylcholinesterase onto tryptophan FMPS-Trp, (FMPS-Trp)Pd(II), and (FMPS-Trp)Pt(II) functionalized spheres. Spectroscopic and microscopic techniques were used in the characterization of the spheres where scanning electron microscopy (SEM) is an essential tool. The (FMPS-Trp)Pt(II)-AChE showed a good affinity to acetylthiocholine chloride (ATCl) and was found to have the ability to catalyze the hydrolysis of ATCl with an apparent Michaelis-Menten constant value of 288 mM. The developed colorimetric process showed good qualitative analytical performance for Phosmet (OPs) detection as low as 10(-7) M. [GRAPHICS] .
  • Küçük Resim
    Öğe
    Synthesis and characterization of Au and Bi2O3 decorated Fe3O4@PAMAM dendrimer nanocomposites for medical applications
    (Springer Heidelberg, 2021) Kurnaz Yetim, Nurdan; Kursun Baysak, Fatma; Koc, Mumin Mehmet; Nartop, Dilek
    Fe3O4 magnetic nanoparticles were produced and covered with TEOS and APTES which were known to reduce the toxic properties of nanoparticles. Nanoparticles were functionalized second-generation PAMAM dendrimers and doped with Au and Bi2O3 nanoparticles where Fe3O4@G2/Au/Bi2O3 nanocomposites were obtained for potential multimodal imaging applications. Physicals structures of the nanocomposites were characterized using SEM and TEM which illustrate that nanoparticles were in composite form. Chemical composition of nanostructures was confirmed using EDX and FTIR. Magnetic characteristics were checked using VSM. It was seen that nanoparticles have superparamagnetic properties which indicate that nanocomposites have potential to be used in MRI and magnetic hyperthermia applications. X-ray imaging properties were confirmed using X-ray imaging and CT imaging. It was confirmed that doping nanoparticles with Au and Bi2O3 nanoparticles significantly enhanced the X-ray tomography contrast enhancement properties which illustrate the theranostic properties of the nanocomposites.