ABSTRACT
Objective To investigate the physical and magnetic properties and cytotoxity of 5-FAM-dextran-coated superparamagnetic iron oxide nanoparticles ( 5-FAM-dextran-Fe3 O4 ) , and to observe the cell-labeling character of these nanoparticles. Methods 5-FAM-dextran-Fe3 O4 were prepared by ultra-sonic and chemical coprecipitation method and the characteristics were evaluated. The size and distribution of 5-FAM-dextran-Fe3 O4 were measured by transmission electron microscope ( TEM) and Malvern Zetasizer. The organic structure of the coating was characterized by fourier translation infrared spectroscopy. The optical imaging ability was measured by ultraviolet visible spectrometer and the susceptibility was measured by vi-brating sample magnetometer. In vitro cytotoxities of 5-FAM-dextran-Fe3 O4 , dextran-Fe3 O4 and Fe3 O4 were detected by MTT assay. The area of labeled neuronal cells was observed by confocal microscopy after incuba-ted with nanoparticles under different magnetic intensities. One-way analysis of variance was used. Results The size of 5-FAM-dextran-Fe3 O4 was homogeneous under TEM, and the diameter ranged from 15 to 25 nm ( average=22 nm) by Malvern Zetasizer. The organic structure of the coating of Fe3 O4 was confirmed by fou-rier translation infrared spectroscopy. Ultraviolet visible spectrometer observation showed that the nanoparti-cles expressed unanimous green fluorescence under ultraviolet activation. The saturation magnetization, residu-al magnetization and coercivity of the nanoparticles by magnetometer detection were 86. 02 A · m2 · kg-1 , 15. 05 A·m2 ·kg-1 and 5414.01 A/m respectively, showing superparamagnetic character. MTT assay re-sults showed that 5-FAM-dextran-Fe3 O4 had no obvious cytotoxicity. The confocal microscopy observation in-dicated that the cell-labeled area reached the maximum under the magnetic field intensity of 500 mT ((0. 880±0.146) mm2, F=320.298, P<0.05). Conclusions 5-FAM-dextran-Fe3O4 prepared by ultra-sonic coprecipitation method have the advantages of small size, good homogeneity and magnetic property. Therefore, they might be used as the fluorescent magnetic bio-probe in laboratory and clinical studies.
ABSTRACT
Objective To investigate the physical and magnetic properties and cytotoxity of 5-FAM-dextran-coated superparamagnetic iron oxide nanoparticles ( 5-FAM-dextran-Fe3 O4 ) , and to observe the cell-labeling character of these nanoparticles. Methods 5-FAM-dextran-Fe3 O4 were prepared by ultra-sonic and chemical coprecipitation method and the characteristics were evaluated. The size and distribution of 5-FAM-dextran-Fe3 O4 were measured by transmission electron microscope ( TEM) and Malvern Zetasizer. The organic structure of the coating was characterized by fourier translation infrared spectroscopy. The optical imaging ability was measured by ultraviolet visible spectrometer and the susceptibility was measured by vi-brating sample magnetometer. In vitro cytotoxities of 5-FAM-dextran-Fe3 O4 , dextran-Fe3 O4 and Fe3 O4 were detected by MTT assay. The area of labeled neuronal cells was observed by confocal microscopy after incuba-ted with nanoparticles under different magnetic intensities. One-way analysis of variance was used. Results The size of 5-FAM-dextran-Fe3 O4 was homogeneous under TEM, and the diameter ranged from 15 to 25 nm ( average=22 nm) by Malvern Zetasizer. The organic structure of the coating of Fe3 O4 was confirmed by fou-rier translation infrared spectroscopy. Ultraviolet visible spectrometer observation showed that the nanoparti-cles expressed unanimous green fluorescence under ultraviolet activation. The saturation magnetization, residu-al magnetization and coercivity of the nanoparticles by magnetometer detection were 86. 02 A · m2 · kg-1 , 15. 05 A·m2 ·kg-1 and 5414.01 A/m respectively, showing superparamagnetic character. MTT assay re-sults showed that 5-FAM-dextran-Fe3 O4 had no obvious cytotoxicity. The confocal microscopy observation in-dicated that the cell-labeled area reached the maximum under the magnetic field intensity of 500 mT ((0. 880±0.146) mm2, F=320.298, P<0.05). Conclusions 5-FAM-dextran-Fe3O4 prepared by ultra-sonic coprecipitation method have the advantages of small size, good homogeneity and magnetic property. Therefore, they might be used as the fluorescent magnetic bio-probe in laboratory and clinical studies.