Snowman-shaped Au-FeO nanoheterodimers were synthesized by thermal decomposition of iron oleate on presynthesized Au nanoparticles. Subsequently performed ligand exchange with nitrosyl tetrafluoroborate provided water solubility and enabled X-ray-induced NO release. These Au-FeO nanoheterodimers combine high- Z material with catalytically active FeO surfaces and, moreover, plasmonic properties with superparamagnetic performance. We could establish synergetic interactions between X-radiation and both the Au and FeO surfaces, which resulted in the simultaneous production of the nitric oxide radical at the FeO surface and the superoxide radical at the Au surface. The surface-confined reaction between these radicals generated peroxynitrite. This highly reactive species may cause nitration of mitochondrial proteins and lipid peroxidation and induce DNA strand breaks. Therefore, high concentrations of peroxynitrite are expected to give rise to severe cellular energetic derangements and thereupon entail rapid cell death. As providing a common platform for X-ray-induced formation of the highly reactive radical nitric oxide, superoxide, and peroxynitrite, nitrosyl tetrafluoroborate functionalized Au-FeO nanosnowmen were shown to exhibit excellent performance as X-ray-enhancing agents in radiation therapy.

Efficient magnetic reactive oxygen species (ROS) formation enhancing agents after X-ray treatment are realized by functionalizing superparamagnetic magnetite (Fe O ) and Co-ferrite (CoFe O ) nanoparticles with self-assembled monolayers (SAMs). The Fe O and CoFe O nanoparticles are synthesized using Massart's coprecipitation technique. Successful surface modification with the SAM forming compounds 1-methyl-3-(dodecylphosphonic acid) imidazolium bromide, or (2-{2-[2-hydroxy-ethoxy]-ethoxy}-ethyl phosphonic acid provides biocompatibility and long-term stability of the Fe O and CoFe O nanoparticles in cell media. The SAM-stabilized ferrite nanoparticles are characterized with dynamic light scattering, X-ray powder diffraction, a superconducting quantum interference device, Fourier transform infrared attenuated total reflectance spectroscopy, zeta potential measurements, and thermogravimetric analysis. The impact of the SAM-stabilized nanoparticles on the viability of the MCF-7 cells and healthy human umbilical vein endothelial cells (HUVECs) is assessed using the neutral red assay. Under X-ray exposure with a single dosage of 1 Gy the intracellular SAM stabilized Fe O and CoFe O nanoparticles are observed to increase the level of ROS in MCF-7 breast cancer cells but not in healthy HUVECs. The drastic ROS enhancement is associated with very low dose modifying factors for a survival fraction of 50%. This significant ROS enhancement effect by SAM-stabilized Fe O and CoFe O nanoparticles constitutes their excellent applicability in radiation therapy.

Theoretical and experimental examination of the bonding situation in uranium complexes bearing terminal hydrochalcogenido and chalcogenido ligands.

We present the synthesis, characterization, and one-electron oxidation of two uranium(IV) complexes, coordinated to the cyclen-anchored tetrakis(aryloxide) ligands tetrakis-hydroxybenzyl-1,4,7,10 tetraazacyclododecane, (ArOH)cyclen; R = Bu, Me. The new uranium(IV) and (V) complexes exhibit an eight-coordinate, tetragonal ligand environment, effecting exceptional stability of the coordinatively unsaturated uranium compounds. Cyclic voltammetry studies reveal redox events ranging from tri- to hexavalent species, covering an electrochemical window of ∼4 V.