Bismuth-Based Nano- and Microparticles in X-Ray Contrast, Radiation Therapy, and Radiation Shielding Applications

Bismuth has gained attention in preclinical research because of its ability to attenuate X-rays and high biocompatibility, which make it an excellent element for use in a biomedical agent or in radiation shielding. Developments in the synthesis of elemental bismuth nano- and microparticles, their X-radiation interactions, and their biological interactions will be reviewed in this chapter. The chapter will pay special focus to emerging medical applications of elemental bismuth nano- and microparticles, including the possibility of targeted molecular X-ray imaging, photo-thermal and X-radiation dose enhancing therapies for cancer treatment, and the construction of flexible radiation shielding materials and X-ray opaque devices

Aerobic Method for the Synthesis of Nearly Size-Monodisperse Bismuth Nanoparticles from a Redox Non-Innocent Precursor

Herein, we report an aerobic synthesis method to produce bismuth nanoparticles (Bi NPs) with average diameters in the range 40-80 nm using commercially available bismuth triiodide (BiI3) as starting material; the method uses only readily available chemicals and conventional laboratory equipment. Furthermore, size data from replicates of the synthesis under standard reaction conditions indicate that this method is highly reproducible in achieving Bi NP populations with low standard deviations in the mean diameters. We also investigated the mechanism of the reaction, which we determined results from the reduction of a soluble alkylammonium iodobismuthate precursor species formed in situ. Under appropriate concentration conditions of iodobismuthate anion, we demonstrate that burst nucleation of Bi NPs results from reduction of Bi3+ by the coordinated, redox non-innocent iodide ligands when a threshold temperature is exceeded. Finally, we demonstrate phase transfer and silica coating of the Bi NPs, which results in stable aqueous colloids with retention of size, morphology, and colloidal stability. The resultant, high atomic number, hydrophilic Bi NPs prepared using this synthesis method have potential for application in emerging X-ray contrast and X-ray therapeutic applications

Tris(1,10-Phenanthroline)Cobalt(II) Triiodide

The asymmetric unit of the title compound, [Co(C12H8N2)3](I3)2, contains one [Co(1,10-phenanthroline)3]2+ cation, half each of two centrosymmetric triiodide anions, and one complete triiodide anion. The title compound was synthesized solvothermally from Co(NO3)2, 1,10-phenanthroline, and SnI2, where the SnI2 reagent serves only as a source of I atoms

Tris(Ethylenediamine)Cobalt(III) Nonaiododibismuthate

The asymmetric unit of the title compound, [Co(C2H8N2)3][Bi2I9], crystallizes in the orthorhombic space group Cmc21. The asymmetric unit contains half of a [Co(en)3]3+ cation (en is ethylenediamine) and half of a [Bi2I9]3- anion. Both species are located on mirror planes, requiring the [Co(en)3]3+ cation to be present as a statistically disordered mixture of both enantiomeric forms. Crystals were grown solvothermally from an ethanol-water solvent mixture using rac-[Co(en)3]I3 and bismuth triiodide as starting materials. The compound is a rare example of a mixed-metal halobismuthate material

Tetrakis[2-(2-Pyridyl)Pyridinium] Tetra-μ\u3csub\u3e3\u3c/sub\u3e-Iodo-Hexa-μ\u3csub\u3e2\u3c/sub\u3e-Iodo-Dodecaiodohexabismuthate and Bis[Tris(2,2\u27-Bipyridine)Ruthenium(II)] Di-μ\u3csub\u3e4\u3c/sub\u3e-Iodo-Octa-μ\u3csub\u3e2\u3c/sub\u3e-Iodo-Dodecaiodohexabismuthate

Crystals of the title compounds were grown solvothermally in an ethanol-water solvent mixture using ruthenium triiodide, 2,2\u27-bipyridine and bismuth triiodide as starting materials. Tetrakis[2-(2-pyridyl)pyridinium] tetra-3-iodo-hexa-2-iodo-dodecaiodohexabismuthate, (C10H9N2)4[Bi6I22], crystallizes in the triclinic space group P and is the major reaction product. The asymmetric unit of this compound consists of half a centrosymmetric [Bi6I22]4- anion and two independent 2,2\u27-bipyridinium cations. The minor product of the reaction is bis[tris(2,2\u27-bipyridine)ruthenium(II)] di-4-iodo-octa-2-iodo-dodecaiodohexabismuthate, [Ru(C10H8N2)3]2[Bi6I22], which also crystallizes in the triclinic space group P. For this compound, the asymmetric unit consists of one full [Ru(2,2\u27-bipyridine)3]2+ cation and half a centrosymmetric [Bi6I22]4- anion. Although both compounds contain a centrosymmetric [Bi6I22]4- anion, the polyhedral arrangement of the distorted BiI6 octahedra in the two compounds is quite different, and the anion of the latter compound has not previously been observed in iodobismuthate chemistry. Formula: (C10H9N2)4[Bi6I22] and [Ru(C10H8N2)3][Bi6I22

\u3cem\u3ecatena\u3c/em\u3e-Poly[[diaquadinitratozinc(II)]bis(μ-1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene)]

The polymeric title complex, [Zn(NO3)2(C24H20N8)(H2O)2]n, features distorted ZnN2O4 octahedra with each ZnII atom being located on an inversion center. Adjacent Zn ions are doubly bridged by two equivalent 1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene ligands to form linear chains

\u3cem\u3ecatena\u3c/em\u3e-Poly[[bis(α-thenoyltrifluoroacetonato-κ\u3csup\u3e2\u3c/sup\u3eO,O\u27)copper(II)]-μ-1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene-κ\u3csup\u3e2\u3c/sup\u3eN:N\u27]

The title compound, [Cu(C8H4F3O2S)2(C12H10N4)]n or [Cu(tta)2(L2)2]n (L2 = 1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene and tta = -thenoyltrifluoroacetonate), consists of undulating chains containing two crystallographically distinct CuII centers that are each located on inversion centers. Each CuII center exhibits distorted octahedral coordination provided by two pyridyl N atoms from two equivalent L2 ligands and four O atoms from two equivalent tta ligands. The chains interact through weak C-FH-C contacts

Маркетинг навколишнього середовища

The photophysical properties of silicon semiconductor nanocrystals (SiNCs) are extremely sensitive to the presence of surface chemical defects, many of which are easily produced by oxidation under ambient conditions. The diversity of chemical structures of such defects and the lack of tools capable of probing individual defects continue to impede understanding of the roles of these defects in SiNC photophysics. We use scanning tunneling spectroscopy to study the impact of surface defects on the electronic structures of hydrogen-passivated SiNCs supported on the Au(111) surface. Spatial maps of the local electronic density of states (LDOS) produced by our measurements allowed us to identify locally enhanced defect-induced states as well as quantum-confined states delocalized throughout the SiNC volume. We use theoretical calculations to show that the LDOS spectra associated with the observed defects are attributable to Si-O-Si bridged oxygen or Si-OH surface defects

pH-Dependent Synthesis and Stability of Aqueous, Elemental Bismuth Glyconanoparticle Colloids: Potentially Biocompatible X-ray Contrast Agents

Taking advantage of a pH-dependent solubility equilibrium, we have developed an aqueous synthesis of chemically and colloidally stable bismuth(0) glyconanoparticles. The synthetic method results in potentially biocompatible elemental bismuth nanoparticles (BiNPs) and involves the reduction of aqueous bismuth(III) cations by sodium borohydride in a pH-controlled solution. Medical-grade dextran (75 000 MW) was found to protect the nanocrystals from oxidation, in addition to promoting colloidal stability and separation of individual nanocrystallites. The rate of particle formation was dependent on synthesis pH, and decreasing the reaction rate by increasing the pH produced a greater number of individual and isolated Bi(0) nanocrystals. Stable, aqueous colloids of the dextran-coated BiNPs decomposed under prolonged light exposure, and the NPs dissolved both in acidic solutions (pH12), but were stable in phosphate buffered saline solution (pH 7.4) and in other aqueous solutions between pH 8 and 10. Bismuth-based nanomaterials have previously been demonstrated to be long-circulating X-ray contrast agents, and we anticipate that these high-atomic-number bismuth(0) glyconanoparticles will find use in similar applications

Facile Synthesis of Ligand-Free Iridium Nanoparticles and Their In Vitro Biocompatibility

High-density inorganic nanoparticles have shown promise in medical applications that utilize radiation including X-ray imaging and as radiation dose enhancers for radiotherapy. We have developed an aqueous synthetic method to produce small (~ 2 nm) iridium nanoparticles (IrNPs) by reduction of iridium(III) chloride using a borohydride reducing agent. Unlike other solution-based synthesis methods, uniform and monodispersed IrNPs are produced without the use of surfactants or other solubilizing ligands. These nanoparticles are highly crystalline as observed by X-ray diffraction and high-resolution transmission electron microscopy (TEM). In vitro metabolic toxicity assays using hepatocyte and macrophage cells demonstrate that both IrNPs and iridium(III) chloride are well tolerated at concentrations of up to 10 μM iridium. Furthermore, the IrNPs were assessed in a hemolytic assay and found to have no significant impact on red blood cells when exposed to concentrations up to 100 μM. Overall, these results support the potential for the in vivo application of this nanomaterial