Gadolinium borate and iron oxide bioconjugates: Nanocomposites of next generation with multifunctional applications.

The systematic investigations concerning the bioconjugation of GdBO3-Fe3O4 nanocomposite and their in vitro biocompatibility with cancer cell lines are reported. The nanocomposites were prepared hydrothermally from magnetite (Fe3O4), borax or boric acid and a Gd3+ salt. Bioconjugation processes were performed with citric acid and fluorescein isothiocyanate-doped silica, followed by the treatment with folic acid. Overall, the procedure involved "bare or PEGylated Fe3O4 as the magnetic core" and "vaterite- or triclinic-type of GdBO3 as the surface borate layer" for comparative evaluation of the results. The successful vectorization of the nanocomposite particles was demonstrated by quantitative and qualitative analytical data. All bioconjugates displayed soft ferromagnetic properties and negative zeta potential values that are appropriate for biological applications. The 10B and 157Gd contents were ca. 1014 atom/µg making them promising agents for BNCT, GdNCT and the combined GdBNCT. The Gd/Fe molar ratios (0.27-0.63) provided the capability for T1- or dual (T1 + T2) magnetic resonance imaging (MRI). In vitro studies were conducted to investigate the efficiency of targeted FA-conjugated versus non-FA conjugated nanoformulations on Mia-Pa-Ca-2, HeLa and A549 cells. Fluorescence microscopy and flow cytometry data unveiled the essential role of the zeta potential competing with folate targeting in the uptake mechanism. The bioconjugated nanoplatforms of GdBO3-Fe3O4 composite, introduced herein, proved to have potential features of next generation agents for magnetically targeted therapy, fluorescence imaging, magnetic resonance imaging/diagnosis and Neutron Capture Therapy.

Carborane-layered double hydroxide nanohybrids for potential targeted- and magnetically targeted-BNCT applications.

Carborane-intercalated layered double hydroxide nanohybrids (CB-LDH) and a magnesium ferrite (MF) supported-CB-LDH core-shell nanocomposite (CB-LDH@MF) are reported. The preparation of nanohybrids were carried out by exchanging the interlayer nitrate groups of Mg-Al-NO3-LDH with monothiol-o-carborane (SCB), 1-methyl-2-carboxyl-o-carborane (MeCB), 1-phenyl-2-carboxyl-o-carborane (PhCB) and 1,12-dicarboxyl-p-carborane (COOHCB) molecules. A magnetic core-shell nanocomposite was further prepared by supporting the COOHCB-LDH nanohybrid on MF nanoparticles. The obtained materials were characterized by means of several physical and chemical methods. Chemical compositions were determined by elemental analysis, ICP measurements and SEM-EDX data. Structural characterization was performed with powder-XRD, FTIR and magnetization measurements. Morphological analyses were conducted with electron microscopy imaging (SEM and TEM). Thermal stabilities were investigated by TGA/DTA. Carborane release from LDH layers was tested by tracing the amount of boron species transferred to the solution phase with ICP-MS measurements. The results verified that the prepared nanohybrids have the potential to be used in Boron Neutron Capture Therapy (BNCT) and magnetically targeted-BNCT applications.

5-Fluorouracil intercalated iron oxide@layered double hydroxide core-shell nano-composites with isotropic and anisotropic architectures for shape-selective drug delivery applications.

We report the synthesis, characterization and in vitro release behavior of anti-cancer drug carrying iron oxide@layered double hydroxide core-shell nanocomposites with sizes ranging from 40 to 300 nm, good drug loading capacities and soft ferromagnetic properties. HRTEM analyses verified that nearly spherical isotropic carriers were obtained by coating spherical magnetite particles while anisotropic carriers were obtained by coating spindle-shaped hematite particles. They both displayed a fluctuating in vitro release profile with a higher release percentage for the anisotropic carrier.

Water oxidation catalysis by birnessite@iron oxide core-shell nanocomposites.

In this work, magnetic nanocomposite particles were prepared for water oxidation reactions. The studied catalysts consist of maghemite (γ-Fe2O3), magnetite (Fe3O4), and manganese ferrite (MnFe2O4) nanoparticles as cores coated in situ with birnessite-type manganese oxide shells and were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermal, chemical, and surface analyses, and magnetic measurements. The particles were found to be of nearly spherical core-shell architectures with average diameter of 150 nm. Water oxidation catalysis was examined using Ce(4+) as the sacrificial oxidant. All core-shell particles were found to be active water oxidation catalysts. However, the activity was found to depend on a variety of factors like the type of iron oxide core, the structure and composition of the shell, the coating characteristics, and the surface properties. Catalysts containing magnetite and manganese ferrite as core materials displayed higher catalytic activities per manganese ion (2650 or 3150 mmolO2 molMn(-1) h(-1)) or per mass than nanoiron oxides (no activity) or birnessite alone (1850 mmolO2 molMn(-1) h(-1)). This indicates synergistic effects between the MnOx shell and the FeOx core of the composites and proves the potential of the presented core-shell approach for further catalyst optimization. Additionally, the FeOx cores of the particles allow magnetic recovery of the catalyst and might also be beneficial for applications in water-oxidizing anodes because the incorporation of iron might enhance the overall conductivity of the material.

Prolate spheroidal hematite particles equatorially belt with drug-carrying layered double hydroxide disks: Ring Nebula-like nanocomposites.

A new nanocomposite architecture is reported which combines prolate spheroidal hematite nanoparticles with drug-carrying layered double hydroxide [LDH] disks in a single structure. Spindle-shaped hematite nanoparticles with average length of 225 nm and width of 75 nm were obtained by thermal decomposition of hydrothermally synthesized hematite. The particles were first coated with Mg-Al-NO3-LDH shell and then subjected to anion exchange with salicylate ions. The resulting bio-nanohybrid displayed a close structural resemblance to that of the Ring Nebula. Scanning electron microscope and transmission electron microscopy images showed that the LDH disks are stacked around the equatorial part of the ellipsoid extending along the main axis. This geometry possesses great structural tunability as the composition of the LDH and the nature of the interlayer region can be tailored and lead to novel applications in areas ranging from functional materials to medicine by encapsulating various guest molecules.

Bioinorganic magnetic core-shell nanocomposites carrying antiarthritic agents: intercalation of ibuprofen and glucuronic acid into Mg-Al-layered double hydroxides supported on magnesium ferrite.

This paper describes the synthesis and characterization of a composite constituted by an antiarthritic agent (AA) intercalated into a layered double hydroxide (LDH) supported on magnesium ferrite. Core-shell nanocomposites were prepared by depositing Mg-Al-NO(3)-LDH on a MgFe(2)O(4) core prepared by calcination of a nonstoichiometric Mg-Fe-CO(3)-LDH. Intercalation of ibuprofen and glucuronate anions was performed by ion-exchange with nitrate ions. The structural characteristics of the obtained products were investigated by powder X-ray diffraction, element chemical analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Morphologies of the nanocomposite particles were examined by scanning electron microscopy and transmission electron microscopy. The products were shown to intercalate substantial amounts of AA with enhanced thermal stabilities. Room-temperature magnetic measurements by vibrating sample magnetometry revealed that the products show soft ferromagnetic properties suitable for potential utilization in magnetic arthritis therapy.

catena-Poly[[[triaquacobalt(II)]-mu-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylato(2-)] 1.72-hydrate].

The Co(II) ion in the title complex {[Co(C5H2N2O4)(H2O)3].1.72H2O}n, has a distorted octahedral coordination geometry comprised of three water ligands, one deprotonated pyrimidine N atom and an adjacent carboxylate O atom of one orotate ligand. The sixth coordination site is occupied by an exocyclic O atom from a neighbouring orotate moiety, and through this interaction a helicoidal chain is formed. The molecules are linked by intramolecular Owater-H...O and intermolecular N-H...O and Owater-H...O hydrogen bonds, forming a three-dimensional network.

Effects of neutral, cationic, and anionic chromium ascorbate complexes on isolated human mitochondrial and genomic DNA.

The relative activities of neutral, cationic, and anionic chromium ascorbate complexes toward isolated human mitochondrial and genomic DNA were investigated at physiologically relevant conditions by agarose gel electrophoresis. A direct relationship between the charge of the Cr(III) species and their DNA-damaging properties was found. The cationic species were found to be fully capable of DNA-cleavage, even in short incubation periods. Incubations were also performed in the presence of amino acids. No apparent effect was observed under the applied experimental conditions to facilitate or prevent damage through the ternary amino acid-Cr-DNA adduct formation or binary chromium-amino acid complex formation.