Special Issue "Synchrotron Radiation Techniques for the Investigation of Nanomaterials"

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: 30 September 2020.

Special Issue Editors

Dr. Marco Scavini
Website
Guest Editor
Dipartimento di Chimica, Università di Milano, Via C. Golgi 19, 20133, Milano, Italy
Interests: solid state chemistry, diffraction, pair distribution function, photons & neutrons, disorder, thermodynamics of defects, strongly correlated systems, ionic conductor
Dr. Mauro Coduri
Website
Guest Editor
Department of Chemistry, University of Pavia, Via Taramelli 12, 27100, Pavia, Italy
Interests: synchrotron radiation, material chemistry, powder diffraction, pair distribution function, phase transformations, intermetallics, catalysis, disorder, ionic conductors

Special Issue Information

Dear Colleagues,

Exploring nano-worlds requires one to keep pushing the limits of technologies forward. In this context, new approaches, techniques, and strategies have been developed in recent years involving the use of synchrotron sources, taking advantage of the extreme versatility of synchrotron radiation.

This Special Issue of Nanomaterials is dedicated to the role of synchrotron radiation probes in the investigation of nanomaterials, starting from a computing approach to simulate and develop experiments, passing through new techniques, devices, and environments developed to study nanomaterials, and ending in scientific results on the structure and properties of nano-materials, -particles, -composites, and -domains.

It is dedicated to the memory of Dr. Claudio Ferrero (ESRF), former head of the data analysis unit of the European Synchrotron ESRF, who spent most of his nights and weekends dedicated to his true mission: performing experiments at all the beamlines of the ESRF.

Dr. Marco Scavini
Dr. Mauro Coduri
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Synchrotron radiation
  • Nanomaterials
  • Nanoparticles
  • Nanodomains
  • Nanocomposites
  • Biological nanostructures
  • Polymeric nanostructures
  • Thin films
  • Absorption
  • Scattering
  • Emission
  • Fluorescence
  • Tomography
  • Simulations

Published Papers (9 papers)

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Research

Open AccessArticle
Local Structure and Magnetism of Fe2O3 Maghemite Nanocrystals: The Role of Crystal Dimension
Nanomaterials 2020, 10(5), 867; https://doi.org/10.3390/nano10050867 - 30 Apr 2020
Abstract
Here we report on the impact of reducing the crystalline size on the structural and magnetic properties of γ-Fe2O3 maghemite nanoparticles. A set of polycrystalline specimens with crystallite size ranging from ~2 to ~50 nm was obtained combining microwave plasma [...] Read more.
Here we report on the impact of reducing the crystalline size on the structural and magnetic properties of γ-Fe2O3 maghemite nanoparticles. A set of polycrystalline specimens with crystallite size ranging from ~2 to ~50 nm was obtained combining microwave plasma synthesis and commercial samples. Crystallite size was derived by electron microscopy and synchrotron powder diffraction, which was used also to investigate the crystallographic structure. The local atomic structure was inquired combining pair distribution function (PDF) and X-ray absorption spectroscopy (XAS). PDF revealed that reducing the crystal dimension induces the depletion of the amount of Fe tetrahedral sites. XAS confirmed significant bond distance expansion and a loose Fe-Fe connectivity between octahedral and tetrahedral sites. Molecular dynamics revealed important surface effects, whose implementation in PDF reproduces the first shells of experimental curves. The structural disorder affects the magnetic properties more and more with decreasing the nanoparticle size. In particular, the saturation magnetization reduces, revealing a spin canting effect. Moreover, a large effective magnetic anisotropy is measured at low temperature together with an exchange bias effect, a behavior that we related to the existence of a highly disordered glassy magnetic phase. Full article
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Open AccessArticle
The Terahertz Dynamics of an Aqueous Nanoparticle Suspension: An Inelastic X-ray Scattering Study
Nanomaterials 2020, 10(5), 860; https://doi.org/10.3390/nano10050860 - 29 Apr 2020
Abstract
We used the high-resolution Inelastic X-ray Scattering beamline of the Advanced Photon Source at Argonne National Laboratory to measure the terahertz spectrum of pure water and a dilute aqueous suspension of 15 nm diameter spherical Au nanoparticles (Au-NPs). We observe that, despite their [...] Read more.
We used the high-resolution Inelastic X-ray Scattering beamline of the Advanced Photon Source at Argonne National Laboratory to measure the terahertz spectrum of pure water and a dilute aqueous suspension of 15 nm diameter spherical Au nanoparticles (Au-NPs). We observe that, despite their sparse volume concentration of about 0.5%, the immersed NPs strongly influence the collective molecular dynamics of the hosting liquid. We investigate this effect through a Bayesian inference analysis of the spectral lineshape, which elucidates how terahertz transport properties of water change upon Au-NP immersion. In particular, we observe a nearly complete disappearance of the longitudinal acoustic mode and a mildly decreased ability to support shear wave propagation. Full article
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Open AccessArticle
Structural Study of Nano-Sized Gahnite (ZnAl2O4): From the Average to the Local Scale
Nanomaterials 2020, 10(5), 824; https://doi.org/10.3390/nano10050824 - 26 Apr 2020
Abstract
Spinel gahnite (ZnAl2O4) has been obtained through a hydrothermal synthesis method with a grain size of about 2 nm. The sample was calcined for a few hours at two different temperatures (800 and 900 °C) in order to obtain [...] Read more.
Spinel gahnite (ZnAl2O4) has been obtained through a hydrothermal synthesis method with a grain size of about 2 nm. The sample was calcined for a few hours at two different temperatures (800 and 900 °C) in order to obtain larger grain sizes to be analyzed by means of powder diffraction with the Rietveld method, and by means of total scattering with the Pair Distribution Function (PDF) method. The idea is to compare the average to the local structure, as a function of increasing grain size. The total scattering data were collected at the European Synchrotron Radiation Facility (ESRF), Grenoble. The samples have been also characterised by means of high resolution Transmission Electron Microscopy (TEM), showing an increasing grain size up to about 9 nm. The average structure presented variations in the inversion degree and an increase in grain size. TEM observations demonstrated that the small crystals are well crystallised: the high resolution images neatly showed the atomic planes, even in the smallest particles. However, the average structure did not properly fit the PDF data in the local region, owing to a slightly different coordination among the octahedra. A new structural model is proposed for the local region of the PDF, that helped our understanding of the differences between a real nanostructured sample and that of a microcrystalline one. The oxygen disorder, due to the inversion grade of the spinel, is demonstrates to be at the basis of the local deviation. No signals of interstitial Zn atoms were detected. Full article
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Open AccessArticle
Structural, Electronic and Magnetic Properties of a Few Nanometer-Thick Superconducting NdBa2Cu3O7 Films
Nanomaterials 2020, 10(4), 817; https://doi.org/10.3390/nano10040817 - 24 Apr 2020
Abstract
Epitaxial films of high critical temperature ( T c ) cuprate superconductors preserve their transport properties even when their thickness is reduced to a few nanometers. However, when approaching the single crystalline unit cell (u.c.) of thickness, T c decreases and eventually, superconductivity [...] Read more.
Epitaxial films of high critical temperature ( T c ) cuprate superconductors preserve their transport properties even when their thickness is reduced to a few nanometers. However, when approaching the single crystalline unit cell (u.c.) of thickness, T c decreases and eventually, superconductivity is lost. Strain originating from the mismatch with the substrate, electronic reconstruction at the interface and alteration of the chemical composition and of doping can be the cause of such changes. Here, we use resonant inelastic x-ray scattering at the Cu L 3 edge to study the crystal field and spin excitations of NdBa 2 Cu 3 O 7 x ultrathin films grown on SrTiO 3 , comparing 1, 2 and 80 u.c.-thick samples. We find that even at extremely low thicknesses, the strength of the in-plane superexchange interaction is mostly preserved, with just a slight decrease in the 1 u.c. with respect to the 80 u.c.-thick sample. We also observe spectroscopic signatures for a decrease of the hole-doping at low thickness, consistent with the expansion of the c-axis lattice parameter and oxygen deficiency in the chains of the first unit cell, determined by high-resolution transmission microscopy and x-ray diffraction. Full article
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Open AccessArticle
Effects of Nanodomains on Local and Long-Range Phase Transitions in Perovskite-Type Eu0.8Ca0.2TiO3–δ
Nanomaterials 2020, 10(4), 769; https://doi.org/10.3390/nano10040769 - 16 Apr 2020
Abstract
The determination of reversible phase transitions in the perovskite-type thermoelectric oxide Eu0.8Ca0.2TiO3–δ is fundamental, since structural changes largely affect the thermal and electrical transport properties. The phase transitions were characterized by heat capacity measurements, Rietveld refinements, and [...] Read more.
The determination of reversible phase transitions in the perovskite-type thermoelectric oxide Eu0.8Ca0.2TiO3–δ is fundamental, since structural changes largely affect the thermal and electrical transport properties. The phase transitions were characterized by heat capacity measurements, Rietveld refinements, and pair distribution function (PDF) analysis of the diffraction data to achieve information on the phase transition temperatures and order as well as structural changes on the local level and the long range. On the long-range scale, Eu0.8Ca0.2TiO3–δ showed a phase transition sequence during heating from cubic at 100 < T < 592 K to tetragonal and finally back to cubic at T > 846 K. The phase transition at T = 592 K (diffraction)/606 K (thermal analysis) was reversible with a very small thermal hysteresis of about 2 K. The local structure at 100 K was composed of a complex nanodomain arrangement of Amm2- and Pbnm-like local structures with different coherence lengths. Since in Eu0.8Ca0.2TiO3–δ the amount of Pbnm domains was too small to percolate, the competition of ferroelectrically distorted octahedra (Amm2 as in BaTiO3) and rigid, tilted octahedra (Pbnm as in CaTiO3) resulted in a cubic long-range structure at low temperatures. Full article
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Open AccessArticle
Structure, Morphology, and Faceting of TiO2 Photocatalysts by the Debye Scattering Equation Method. The P25 and P90 Cases of Study
Nanomaterials 2020, 10(4), 743; https://doi.org/10.3390/nano10040743 - 13 Apr 2020
Abstract
Characterization of functional nanocrystalline materials in terms of quantitative determination of size, size dispersion, type, and extension of exposed facets still remains a challenging task. This is particularly the case of anisotropically shaped nanocrystals (NCs) like the TiO2 photocatalysts. Here, commercially available [...] Read more.
Characterization of functional nanocrystalline materials in terms of quantitative determination of size, size dispersion, type, and extension of exposed facets still remains a challenging task. This is particularly the case of anisotropically shaped nanocrystals (NCs) like the TiO2 photocatalysts. Here, commercially available P25 and P90 titania nanopowders have been characterized by wide-angle X-ray total scattering techniques. Synchrotron data were modelled by the reciprocal space-based Debye scattering equation (DSE) method using atomistic models of NC populations (simultaneously carrying atomic and nanoscale structural features) for both anatase and rutile phases. Statistically robust descriptors are provided of size, morphology, and {101} vs. {001} facet area of truncated tetragonal bipyramids for anatase, jointly to polymorph quantification. The effects of using the proper NC shape on the X-ray diffraction pattern are analyzed in depth through DSE simulations by considering variable bipyramid aspect ratios (resulting in different {101} vs. {001} surface) and relative dispersion in a bivariate manner. We demonstrate that using prismatic NCs having equal volume and aspect ratio as bipyramids provides reasonably accurate sizes and {101} and {001} surface areas of the parent morphology. Full article
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Open AccessArticle
Pressure Induced Stability Enhancement of Cubic Nanostructured CeO2
Nanomaterials 2020, 10(4), 650; https://doi.org/10.3390/nano10040650 - 31 Mar 2020
Abstract
Ceria (CeO2)-based materials are widely used in applications such as catalysis, fuel cells and oxygen sensors. Its cubic fluorite structure with a cell parameter similar to that of silicon makes it a candidate for implementation in electronic devices. This structure is [...] Read more.
Ceria (CeO2)-based materials are widely used in applications such as catalysis, fuel cells and oxygen sensors. Its cubic fluorite structure with a cell parameter similar to that of silicon makes it a candidate for implementation in electronic devices. This structure is stable in a wide temperature and pressure range, with a reported structural phase transition to an orthorhombic phase. In this work, we study the structure of CeO2 under hydrostatic pressures up to 110 GPa simultaneously for the nanometer- and micrometer-sized powders as well as for a single crystal, using He as the pressure-transmitting medium. The first-order transition is clearly present for the micrometer-sized and single-crystal samples, while, for the nanometer grain size powder, it is suppressed up to at least 110 GPa. We show that the stacking fault density increases by two orders of magnitude in the studied pressure range and could act as an internal constraint, avoiding the nucleation of the high-pressure phase. Full article
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Open AccessArticle
K+ vs. Na+ Effects on the Self-Assembly of Guanosine 5′-Monophosphate: A Solution SAXS Structural Study
Nanomaterials 2020, 10(4), 629; https://doi.org/10.3390/nano10040629 - 28 Mar 2020
Abstract
The hierarchical process of guanosine (G) self-assembly, leading in aqueous solution and in the presence of metal cations to the formation of G-quadruplexes, represents an intriguing topic both for the biological correlation with telomerase activity and for the nano-technological applications, as demonstrated by [...] Read more.
The hierarchical process of guanosine (G) self-assembly, leading in aqueous solution and in the presence of metal cations to the formation of G-quadruplexes, represents an intriguing topic both for the biological correlation with telomerase activity and for the nano-technological applications, as demonstrated by the current measured in a quadruplex wire 100 nm long. Similar to G-rich DNA sequences and G-oligonucleotides, the guanosine 5′-monophosphate (GMP) self-aggregates in water to form quadruplexes. However, due to the absence of a covalent axial backbone, this system can be very useful to understand the chemical-physical conditions that govern the guanosine supramolecular aggregation. We have then investigated by in-solution Synchrotron Small Angle X-ray Scattering technique the role of different cations in promoting the quadruplex formation as a function of concentration and temperature. Results show how potassium, with its peculiar biological traits, favours the G-quadruplex elongation process in respect to other cations (Na + , but also NH 4 + and Li + ), determining the longest particles in solution. Moreover, the formation and the elongation of G-quadruplexes have been demonstrated to be controlled by both GMP concentration and excess cation content, even if they specifically contribute to these processes in different ways. The occurrence of condensed liquid crystalline phases was also detected, proving that excess cations play also unspecific effects on the effective charges on the G-quadruplex surface. Full article
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Open AccessArticle
The Structure and Chemical Composition of the Cr and Fe Pyrolytic Coatings on the MWCNTs’ Surface According to NEXAFS and XPS Spectroscopy
Nanomaterials 2020, 10(2), 374; https://doi.org/10.3390/nano10020374 - 21 Feb 2020
Abstract
The paper is devoted to the structure and properties of the composite material based on multi-walled carbon nanotubes (MWCNTs) covered with pyrolytic iron and chromium. Fe/MWCNTs and Cr/MWCNTs nanocomposites have been prepared by the metal organic chemical vapor deposition (MOCVD) growth technique using [...] Read more.
The paper is devoted to the structure and properties of the composite material based on multi-walled carbon nanotubes (MWCNTs) covered with pyrolytic iron and chromium. Fe/MWCNTs and Cr/MWCNTs nanocomposites have been prepared by the metal organic chemical vapor deposition (MOCVD) growth technique using iron pentacarbonyl and bis(arene)chromium compounds, respectively. Composites structures and morphologies preliminary study were performed using X-ray diffraction, scanning and transmission electron microscopy and Raman scattering. The atomic and chemical composition of the MWCNTs’ surface, Fe-coating and Cr-coating and interface—(MWCNTs surface)/(metal coating) were studied by total electron yield method in the region of near-edge X-ray absorption fine structure (NEXAFS) C1s, Fe2p and Cr2p absorption edges using synchrotron radiation of the Russian-German dipole beamline (RGBL) at BESSY-II and the X-ray photoelectron spectroscopy (XPS) method using the ESCALAB 250 Xi spectrometer and charge compensation system. The absorption cross sections in the NEXAFS C1s edge of the nanocomposites and MWCNTs were measured using the developed approach of suppressing and estimating the contributions of the non-monochromatic background and multiple reflection orders radiation from the diffraction grating. The efficiency of the method was demonstrated by the example of the Cr/MWCNT nanocomposite, since its Cr2p NEXAFS spectra contain additional C1s NEXAFS in the second diffraction order. The study has shown that the MWCNTs’ top layers in composite have no significant destruction; the MWCNTs’ metal coatings are continuous and consist of Fe3O4 and Cr2O3. It is shown that the interface between the MWCNTs and pyrolytic Fe and Cr coatings has a multilayer structure: a layer in which carbon atoms along with epoxy –C–O–C– bonds form bonds with oxygen and metal atoms from the coating layer is formed on the outer surface of the MWCNT, a monolayer of metal carbide above it and an oxide layer on top. The iron oxide and chromium oxide adhesion is provided by single, double and epoxy chemical binding formation between carbon atoms of the MWCNT top layer and the oxygen atoms of the coating, as well as the formation of bonds with metal atoms. Full article
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Nanostructure of unconventional liquid crystals investigated by synchrotron radiation
Authors:
Vita, F.C. Adamo, M. Pisani and O. Francescangeli *
Affiliation: Dipartimento di Scienze e Ingegneria della Materia, dell’Ambiente ed UrbanisticaUniversità Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
* Corresponding author: [email protected]
Absract: Among the variety of soft materials currently investigated for their promising technological applications, liquid crystals (LCs) play a prominent role because of the wealth of supramolecular structures that they exhibit and their potential to reflect specific nanostructural features into unconventional macroscopic properties. In this paper we review a number of recent experimental studies performed with synchrotron radiation to investigate the nanoscale structure of new unconventional LCs and LC-based soft materials of high fundamental and technological impact. These include bent-core (or banana-shaped) mesogens, all-aromatic mesogens, high performance thermosets and polymer dispersed LCs. In all cases, synchrotron radiation combined with ad-hoc experimental setup has made it possible to investigate the details of the inherent LC (orientational and positional) order featuring the mesophases and responsible for these peculiar properties. The unconventional properties of the investigated materials were found to result from the inherent peculiar orientational and/or positional order of the nematic mesophases specifically involved.

Title: The Terahertz Dynamics of an Aqueous Nanoparticle Suspension: An Inelastic X-ray Scattering Study
Authors: Alessio De Francesco,1 Luisa Scaccia,2  Ferdinando Formisano,1 Marco Maccarini,3 Ahmet Alatas,4 and Alessandro Cunsolo5
Affiliations:
1 Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali c/o OGG and Institut Laue Langevin, 71 avenue des Martyrs, 38042 Grenoble, France.
2 Dipartimento di Economia e Diritto, Università di Macerata, Via Crescimbeni 20, 62100 Macerata, Italy.
3 Université Grenoble-Alpes - Laboratoire TIMC/IMAG (UMR CNRS 5525), Pavillon Taillefer, Domaine de la Merci, 38700 La Tronche, France.
4 Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
5 National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA.
Abstract: We used the high-resolution Inelastic X-ray Scattering beamline of the Advanced Photon Source at Argonne National Laboratory to jointly measure the terahertz spectrum of pure water and a dilute aqueous suspension of 15 nm diameter Au nanoparticles (NPs). We observe that, despite their sparse volume concentration of about .5%, the immersed NPs strongly influence collective molecular dynamics of the hosting liquid. We investigate this effect through a Bayesian inference analysis of the spectral lineshape, which ultimately elucidates how terahertz transport properties of water change upon NP immersion.

Title: The structure and chemical composition of the pyrolytic coatings of Cr and Fe on the surface of MWCNTs according to NEXAFS and XPS spectroscopy
Abstract:
The paper is devoted to the structure and properties of the composite material based on multi-walled carbon nanotubes (MWCNT) covered with pyrolytic Fe and Cr. Composites (pyrolytic Fe)/MWCNTs and (pyrolytic Cr)/MWCNTs have been prepared by the metal organic chemical vapor deposition (MOCVD) growth technique using iron pentacarbonyl and bis(arene)chromium compounds, respectively. Preliminary composites structures and morphologies were studied using X-ray diffraction and scanning electron microscopy. The atomic and chemical composition of MWCNTs surface, Fe-coating and Cr-coating and interface – (MWCNTs surface)/(metal coating) were studied by total electron yield method in the region of NEXAFS C1s-, Fe2p- and Cr2p-absorption edges with using synchrotron radiation of Russian-German dipole beamline (RGBL) at BESSY-II. The study has shown that MWCNTs top layers in composite have no significant destruction; the MWCNTs metal coatings are continuous and consist of Fe3O4 and Cr2O3. It is shown that the interface between MWCNT and pyrolytic Fe and Cr coatings has a multilayer structure: a layer in which carbon atoms along with epoxy -C – O – C- bonds form bonds with oxygen and metal atoms from the coating layer is formed on the outer surface of the MWCNT, a monolayer of metal carbide above it and an oxide layer on top. The iron oxide and chromium oxide adhesion is provided by single, double and epoxy chemical binding formation between carbon atoms of the MWCNTs top layer and the oxygen atoms of the coating, as well as the formation of bonds with metal atoms.
Keywords: NEXAFS, XPS, MOCVD, total electron yield, multi-walled carbon nanotube, nanocomposite (pyrolitic Cr)/MWCNTs, (pyrolitic Fe)/MWCNTs.

Title: Synchrotron based characterization of hexagonal and cubic phases loaded with Gold(I) phosphane compounds as anticancer drug delivery systems
Authors:
Paola Astolfi1, Michela Pisani1*, Elisabetta Giorgini2, Barbara Rossi3, Alessandro Damin4, Francesco Vita1, Oriano Francescangeli1, Lorenzo Luciani,5 Rossana Galassi5
Affiliations:
1 Dipartimento SIMAU, Università Politecnica delle Marche, Via Brecce Bianche, Ancona, I-60131.
2 Dipartimeto DiSVA, Università Politecnica delle Marche, Via Brecce Bianche, Ancona, I-60131.
3 Elettra - Sincrotrone Trieste S.C.p.A., S.S. 14 - km 163.5, Basovizza, Trieste, I-34149.
4 Department of Chemistry, NIS Centre and INSTM Reference Centre University of Turin, Via G. Quarello 15, I-10135Turin, Italy 
5 Scuola di Scienze e Tecnologie, Divisione Chimica, Università di Camerino, Via Sant’Agostino, I-62032.
Abstract: Recently, a renewed interest has been addressed to gold(I) phosphane compounds as new protagonists in cancer therapy. A class of phosphane gold(I) complexes containing azolate ligands has been successfully tested against several cancer lines. Even though the anticancer activity of gold(I) phosphane compounds is thoroughly ascertained, no studies have been devoted to the possibility of their delivery in nanovectors. Herein, nonlamellar lyotropic liquid crystalline lipid nanosystems, a promising class of smart materials, have been used to encapsulate Gold(I) azolate/phosphane complexes. In particular, ((triphenylphosphine)-gold(I)-(4,5-dichloroimidazolyl-1H-1yl)) (C-I) and ((triphenylphosphine)-gold(I)-(4,5-dicyanoimidazolyl-1H-1yl)) (C-II) have been encapsulated in different lipid matrix such as phytantriol, DOPE and monoolein (GMO). An integrated experimental approach involving X-ray diffraction and UV Resonant Raman spectroscopy based on synchrotron light and ATR-FTIR spectroscopy has been employed to establish the effects of drug encapsulation on the structure and phase behavior of the mesophases.  Gold(I) complexes C-I and C-II are successfully encapsulated in the three lipid matrices and, especially, the UVRR spectra show spectral changes occurring upon loading, mainly involving the phosphane moiety of the complexes. Compound C-I encapsulation results in a greater effect on the phase behavior of GMO and Phytantriol compared to C-II.

Title: Structural study of-nano sized gahnite (ZnAl2O4): from the average to the local scale
Authors: Giorgia Confalonieri1*, Nicola Rotiroti1, Andrea Bernasconi1**, Monica Dapiaggi1
Affilliations:
1 Università degli Studi di Milano, Dipartimento di Scienze della Terra, via Botticelli 23, 20133 Milano (Italy)
* currently at Università degli Studi di Modena e Reggio Emilia, Dipartimento di Scienze Chimiche e Geologiche, via Giuseppe Campi 103, 41125 Modena (Italy)
** currently at Ideal Standard International, Via Cavassico Inferiore 160, 32026 Trichiana (BL), Italy
Abstract: The spinel gahnite (ZnAl2O4) has been obtained, through a hydrothermal synthesis method, with a grain size of about 2 nm. The sample was calcined for a few hours at two different temperatures (800 and 900°C), in order to obtain larger grain sizes, to be analyzed by means of powder diffraction with the Rietveld method, and by means of total scattering with the PDF method. The idea is to compare the average and the local structure, as a function of increasing grain size. Total scattering data were collected @ESRF. The samples have been also characterized by means of high resolution TEM, showing an increasing grain size, up to 7 nm. The average structure showed variations in the inversion degree, and an increase in grain size. TEM observations showed that the small crystals are well crystallized: the high-resolution images showed neatly the atomic planes even in the smallest particles. However, the average structure did not fit properly the PDF data in the local region, owing to a slightly different coordination among the octahedra.

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