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BACKGROUND: Magnetic resonance imaging (MRI) contrast agents have an important role to differentiate healthy and diseased tissues. Access and design new contrast agents for the optimal use of MRI are necessary. This study aims to evaluate iron oxide-4A nanocomposite ability to act as a magnetic resonance imaging contrast agent. MATERIAL AND METHODS: Iron oxide-4A nanocomposite (F4A) was synthesized. MTT assay was used to consider the nanocomposite safety for cell culture. The T1 and T2 relaxation times were measured using a 1.5 Tesla clinical MRI scanner. Then the corresponding relaxivities were determined. RESULTS: The average particle diameter of the nanocomposite was 50 to 100 nm based on scanning electron microscope (SEM) image. A linear relationship between relaxation rates and the Fe concentration of the nanocomposite was obtained. The T1 and T2 relaxivities of the nanocomposite were calculated 5.413 and 1092.1 mM-1.s-1, respectively which led to the T2/T1 relaxivity ratio of 201.75. CONCLUSION: The high T2/T1 relaxivity ratio of the iron oxide-4A nanocomposite confirms it's potential to act as a T2 contrast agent.
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Current research has focused on the preparation of Zinc-clinoptilolite/Graphene Oxide (Zn-Clin/GO) hybrid nanostructure and investigating its biocompatibility for the first time. As prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Thermo gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). In order to use it as a drug carrier two important factors were investigated: cytocompatibility of nanocomposites and their drug loading capacity. The results showed that the prepared nanocomposite is cytocompatible and its high loading capacity and slow release performance for Doxorubicin (DOX), as a cancer drug, proved that it can be used as a drug carrier. At last in-vitro toxicity of DOX loaded nanocomposite was compared with pure DOX.
Asunto(s)
Doxorrubicina/química , Portadores de Fármacos/química , Grafito/química , Nanocompuestos/química , Zeolitas/química , Zinc/química , Células A549 , Antibióticos Antineoplásicos/química , Antibióticos Antineoplásicos/farmacología , Antibióticos Antineoplásicos/toxicidad , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/farmacología , Doxorrubicina/toxicidad , Portadores de Fármacos/toxicidad , Humanos , Microscopía Electrónica de Rastreo , Nanocompuestos/toxicidad , Óxidos/química , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría , Difracción de Rayos XRESUMEN
AIM: The aim of the present study was to compare the antibacterial properties of PLGA polymer containing ZnO, Ag and ZnO/Ag nanoparticles with those of 2.5% NaOCl in root canals contaminated with Enterococcus faecalis. METHODS: A total of 100 maxillary central incisors were selected. After the crowns were removed to achieve 12-mm-length roots, the root canals were prepared with RaCe rotary system. The samples were sterilized; then 200 µL of E. faecalis suspension (ATCC 29212) was placed in each root canal. The samples were divided into 5 groups based on the antibacterial agent used. Group 1 served as the control group. In group 2 the polymer suspension containing ZnO nanoparticles, in group 3 the polymer solution containing ZnO/Ag nanoparticles, in group 4 the polymer solution containing Ag nanoparticles and in group 5, 2.5% NaOCl were used. After 24 hours, a solution was prepared using dentin chips from each root canal and placed on agar plates, followed by colony-forming units (CFU) count determination. Means ± standard deviations were calculated and Kruskal-Wallis test was used to evaluate the antibacterial properties of different irrigation agents. Mann-Whitney U test was used for two-by-two comparisons of the groups, with the level of significance being set at 0.05. RESULTS: The maximum and minimum CFU counts were observed in the control and NaOCl groups, respectively. In the polymer groups, the maximum and minimum CFU counts were observed in the Ag and ZnO/Ag groups, respectively. There were significant differences in CFU counts between the study groups after application of irrigation solutions (P<0.05). Two-by-two comparisons of the groups using Mann-Whitney U test showed significant differences between all the study groups (P<0.05), except for groups ZnO and Ag (P=0.7). CONCLUSION: Sodium hypochlorite solution was more effective than copolymer containing nanoparticles and of all the tested nanoparticles; ZnO/Ag nanoparticles exhibited the highest antibacterial activity.