A novel samarium-doped spherical-like ZnO hierarchical nanostructure (Sm/ZnO) was synthesized via a facile and surfactant-free chemical solution route. The as-synthesized products were characterized by X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, field emission scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The results revealed that Sm ion was successfully doped into ZnO. It was also observed that the Sm doping increased the visible light absorption ability of Sm/ZnO and a red shift for Sm/ZnO appeared when compared to pure ZnO. The photocatalytic studies revealed that the Sm/ZnO exhibited excellent photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) compared with the pure ZnO and commercial TiO2 under visible light irradiation. The photocatalytic enhancement of Sm/ZnO products was attributed to their high charge separation efficiency and ·OH generation ability as evidenced by the photoluminescence spectra. The photocatalytic investigation also showed that various parameters exerted their individual influence on the degradation rate of 2,4-DCP. By using a certain of radical scavengers, ·OH was determined to play a pivotal role for the 2,4-DCP degradation. Moreover, the Sm/ZnO could be easily separated and reused, indicating great potential for practical applications in environmental cleanup.
We produced an enteric-coated gelatine capsule containing neutron-activated (153)Sm-labelled resin beads for use in gastrointestinal motility studies. In vitro test in simulated gastrointestinal environment and in vivo study on volunteers were performed. Scintigraphic images were acquired from ten volunteers over 24h while blood and urine samples were collected to monitor the presence of (153)Sm. All the capsules remained intact in stomach. This proved to be a safe and practical oral capsule formulation for whole gut transit scintigraphy.
In the presence of hydroxyl and amine groups, chitosan is highly reactive; therefore, it could be used as a carrier in drug delivery. For this study, chitosan-Sm complexes with different concentrations of samarium from 2.5 to 25 wt.% have been successfully synthesized by the impregnation method. Chitosan combined with Sm3+ ions produced a drug carrier material with fluorescence properties; thus, it could also be used as an indicator of drug release with ibuprofen (IBU) as a model drug. We evaluated the spectroscopic and interaction properties of chitosan and Sm3+ ions, the interaction of chitosan-Sm matrices with IBU as a model drug, and the effect of Sm3+ ions addition on the chitosan ability to adsorb the drug. The result showed that the hypersensitive fluorescence intensity of chitosan-Sm (2.5 wt.%) is higher than the others, even though the adsorption efficiency of chitosan-Sm 2.5wt.% is lower (29.75%) than that of chitosan-Sm 25 wt.% (33.04%). Chitosan-Sm 25 wt.% showed the highest efficiency of adsorption of ibuprofen (33.04%). In the release process of ibuprofen from the chitosan-Sm-IBU matrix, the intensity of orange fluorescent properties in the hypersensitive peak of 4G5/2→6H7/2 transition at 590 nm was observed. Fluorescent intensity increased with the cumulative amount of IBU released; therefore, the release of IBU from the Sm-modified chitosan complex can be monitored by the changes in fluorescent intensity.
This work investigated the anti-amoebic activity of two samarium (Sm) complexes, the acyclic complex [bis(picrato)(pentaethylene glycol)samarium(III)] picrate-referred to as [Sm(Pic)2(EO5)](Pic)-and the cyclic complex [bis(picrato)(18-crown-6)samarium(III)] picrate-referred to as [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morphological transformation of the protozoa Acanthamoeba from its native trophozoite form carrying a spine-like structure called acanthopodia, to round-shaped cells with loss of the acanthopodia structure, a trademark response to environmental stress. Further investigation, however, revealed that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic complex (0.7 μg/mL) was ~ 10-fold lower than IC50 of the cyclic Sm complex (6.5 μg/mL). Secondly, treatment of the Acanthamoeba with the acyclic complex caused apoptosis of the treated cells, while the treatment with the cyclic complex caused necrosis evident by the leakage of the cell membrane. Both treatments induced DNA damage in Acanthamoeba. Finally, a molecular docking simulation revealed the potential capability of the acyclic complex to form hydrogen bonds with profilin-a membrane protein present in eukaryotes, including Acanthamoeba, that plays important roles in the formation and degradation of actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at least in part, for the much higher cytotoxicity of the acyclic complex and also possibly, for the observed differences in the cytotoxicity traits. Nonetheless, with IC50 values of