FT-IR Investigation of the State of Iron(III) Chloride Clusters Confined in AOT Reverse Micelles Dispersed in Carbon Tetrachloride

The state of the water-soluble salt iron(III) chloride in AOT reverse micelles dispersed in carbon tetrachloride has been investigated by FT-IR spectroscopy. Interestingly, while the entrapment of a lot of water-soluble inorganic salts in AOT reverse micelles requires preliminarily the presence of significant amounts of water within the micellar core, solubilization of FeCl₃ occurs without the need to add water in the micellar solution reaching the very high solubility value, expressed as the maximum salt-to-surfactant molar ratio, of 1.30. The analysis of the spectral features of the investigated samples leads to hypothesize that iron(III) chloride is confined within the reverse micellar core as small size melted clusters of ionic species arising from the reactions

An integrated approach for the systematic evaluation of polymeric nanoparticles in healthy and diseased organisms

Innovative strategies that utilize nanoparticles (NPs) for a better delivery of drugs and to improve their therapeutic efficacy have been widely studied in many clinical fields, including oncology. To develop safe and reliable devices able to reach their therapeutic target, a hierarchical characterization of NP interactions with biological fluids, cells, and whole organisms is fundamental. Unfortunately, this aspect is often neglected and the development of standardized characterization methods would be of fundamental help to better elucidate the potentials of nanomaterials, even before the loading of the drugs. Here, we propose a multimodal in vitro/in vivo/ex vivo platform aimed at evaluating these interactions for the selection of the most promising NPs among a wide series of materials. To set the system, we used non-degradable fluorescent poly(methyl-methacrylate) NPs of different sizes (50, 100, and 200 nm) and surface charges (positive and negative). First we studied NP stability in biological fluids. Then, we evaluated NP interaction with two cell lines of triple-negative breast cancer (TNBC), 4T1, and MDA-MB231.1833, respectively. We found that NPs internalize in TNBC cells depending on their physico-chemical properties without toxic effects. Finally, we studied NP biodistribution in terms of tissue migration and progressive clearance in breast-cancer bearing mice. The use of highly stable poly(methyl-methacrylate) NPs enabled us to track them for a long time in cells and animals. The application of this platform to other nanomaterials could provide innovative suggestions for the development of a systematic method of characterization to select the most reliable nanodrug candidates for biomedical applications.     

Characterization of gas phase aggregates of bis(2‐ethylhexyl)sulfosuccinate (AOT) and divalent metal ions. Elimination of radical species in the decomposition pathways of even‐electron [AOTMIICl2]– anions

Structure and properties of even‐electron anionic species formed by bis(2‐ethylhexyl)sulfosuccinate (AOT) and divalent metal ions (M^II) with stoichiometry [AOTM^IICl₂]^– have been investigated by using electrospray ionization and different mass spectrometry techniques, such as high resolution, accurate mass measurements, collision‐induced dissociation (CID) multiple‐stage mass spectrometry. Owing to CID, eliminations of neutrals, mainly consisting in hydrochloric acid, 2‐ethyl‐1‐hexene and 2‐ethylhexanol, and an unexpected loss of an alkyl radical have been observed. The radical anions [C₄HO₆SM^IICl]^–? so produced have been characterized by MS³ experiments. Density functional theory calculations have been carried out for investigating structure and stability of the ionic species formed in the decomposition pathways. Copyright © 2012 John Wiley & Sons, Ltd.     

Micro‐Raman spectroscopy and SEM/EDX applied to improve the zircon fission track method used for dating geological formations

The zircon mineral is widely studied in geochronology. In the case of the fission track method (FTM), the age is determined by the density of fission tracks at the zircon surface, which can be observed with an optical microscope after an appropriate chemical treatment (etching). The etching must be isotropic at the zircon grain surface to be used in the FTM, which leads those zircon grains whose etching is anisotropic to be discarded. The only reason for this discarding is the nonuniform morphology of the surface grain seen by optical microscopy, that is, no further physicochemical analysis is performed. In this work, combining micro‐Raman and scanning electron microscopy (SEM) to study the etching anisotropy, it was shown that zircon grains that present at least one area at the surface where the density of fission track is uniform can be used in the FTM. The micro‐Raman showed characteristic spectra of the standard zircon sample either from the areas where there are tracks or from where there are not. The only difference found was in the Raman bandwidths, which were broader for the areas with higher density of fission tracks. This suggests simply a decrease in the relative percentage of the crystalline/amorphous phases at these areas. The SEM/energy dispersive spectrometry (EDX) showed that there were no significant differences in the principal chemical composition at the areas with and without fission tracks. Copyright © 2008 John Wiley & Sons, Ltd.