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Procopio A, Malucelli E, Pacureanu A, Cappadone C, Farruggia G, Sargenti A, Castiglioni S, Altamura D, Sorrentino A, Giannini C, Pereiro E, Cloetens P, Maier JAM, Iotti S. Chemical Fingerprint of Zn-Hydroxyapatite in the Early Stages of Osteogenic Differentiation. ACS CENTRAL SCIENCE 2019; 5:1449-1460. [PMID: 31482128 PMCID: PMC6716342 DOI: 10.1021/acscentsci.9b00509] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Indexed: 06/01/2023]
Abstract
The core knowledge about biomineralization is provided by studies on the advanced phases of the process mainly occurring in the extracellular matrix. Here, we investigate the early stages of biomineralization by evaluating the chemical fingerprint of the initial mineral nuclei deposition in the intracellular milieu and their evolution toward hexagonal hydroxyapatite. The study is conducted on human bone mesenchymal stem cells exposed to an osteogenic cocktail for 4 and 10 days, exploiting laboratory X-ray diffraction techniques and cutting-edge developments of synchrotron-based 2D and 3D cryo-X-ray microscopy. We demonstrate that biomineralization starts with Zn-hydroxyapatite nucleation within the cell, rapidly evolving toward hexagonal hydroxyapatite crystals, very similar in composition and structure to the one present in human bone. These results provide experimental evidence of the germinal role of Zn in hydroxyapatite nucleation and foster further studies on the intracellular molecular mechanisms governing the initial phases of bone tissue formation.
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Terzi A, Gallo N, Bettini S, Sibillano T, Altamura D, Campa L, Natali ML, Salvatore L, Madaghiele M, De Caro L, Valli L, Sannino A, Giannini C. Investigations of Processing-Induced Structural Changes in Horse Type-I Collagen at Sub and Supramolecular Levels. Front Bioeng Biotechnol 2019; 7:203. [PMID: 31552231 PMCID: PMC6736615 DOI: 10.3389/fbioe.2019.00203] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/06/2019] [Indexed: 11/19/2022] Open
Abstract
The aim of this work is to evaluate the effects of different extraction and material processing protocols on the collagen structure and hierarchical organization of equine tendons. Wide and Small Angle X-ray Scattering investigations on raw powders and thin films revealed that not only the extraction and purification treatments, but also the processing conditions may affect the extent of the protein crystalline domain and induce a nanoscale “shield effect.” This is due to the supramolecular fiber organization, which protects the atomic scale structure from the modifications that occur during fabrication protocols. Moreover, X-ray analyses and Fourier Transform Infrared spectroscopy performed on the biomaterial sheds light on the relationship between processing conditions, triple helical content and the organization in atomic and nanoscale domains. It was found that the mechanical homogenization of the slurry in acidic solution is a treatment that ensures a high content of super-organization of collagen into triple helices and a lower crystalline domain in the material. Finally, mechanical tensile tests were carried out, proving that the acidic solution is the condition which most enhances both mechanical stiffness and supramolecular fiber organization of the films.
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Scarfiello R, Cesari A, Altamura D, Masi S, Nobile C, Balzano F, Giannini C, Grillo V, Tavabi AH, Dunin-Borkowski RE, Uccello-Barretta G, Cozzoli PD, Rizzo A. Mechanistic insight into the formation of colloidal WS 2 nanoflakes in hot alkylamine media. NANOSCALE ADVANCES 2019; 1:2772-2782. [PMID: 36132722 PMCID: PMC9418938 DOI: 10.1039/c9na00279k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 05/23/2019] [Indexed: 06/16/2023]
Abstract
Developing convenient and reliable synthetic methodologies for solution processable 2D layered ultrathin nanostructures with lateral size control is one of the major challenges for practical applications. In this study, a rational understanding a long-chain amphiphilic surfactant assisted non-hydrolytic synthesis that is able to generate dimension-controllable 2D-WS2 nanocrystal flakes in a single-step protocol is proposed. The evolution of the starting soft organic-inorganic lamellar template into ultrathin few-layer 2D-WS2 nanostructures with lateral size modulation over a range between 3 and 30 nm is monitored. The initial formation of WS2 nanoseeds occurs in a self-assembled sacrificial precursor source, acting as a template, where larger two-dimensional nanostructures can grow without undergoing significant thickness variation. Overall, the chemical nature and steric hindrance of the alkylamines are essential to modulate the reactivity of such WS2 nanoclusters, which correlate with the lateral size of the resulting nanoflakes.
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Migliaccio L, Manini P, Altamura D, Giannini C, Tassini P, Maglione MG, Minarini C, Pezzella A. Evidence of Unprecedented High Electronic Conductivity in Mammalian Pigment Based Eumelanin Thin Films After Thermal Annealing in Vacuum. Front Chem 2019; 7:162. [PMID: 30972328 PMCID: PMC6443883 DOI: 10.3389/fchem.2019.00162] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/04/2019] [Indexed: 11/16/2022] Open
Abstract
Melanin denotes a variety of mammalian pigments, including the dark electrically conductive eumelanin and the reddish, sulfur-containing, pheomelanin. Organic (bio)electronics is showing increasing interests in eumelanin exploitation, e.g., for bio-interfaces, but the low conductivity of the material is limiting the development of eumelanin-based devices. Here, for the first time, we report an abrupt increase of the eumelanin electrical conductivity, revealing the highest value presented to date of 318 S/cm. This result, obtained via simple thermal annealing in vacuum of the material, designed on the base of the knowledge of the eumelanin chemical properties, also discloses the actual electronic nature of this material's conduction.
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Camposeo A, Granger DB, Parkin SR, Altamura D, Giannini C, Anthony JE, Pisignano D. Directed Functionalization Tailors the Polarized Emission and Waveguiding Properties of Anthracene-Based Molecular Crystals. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2019; 31:1775-1783. [PMID: 30918420 PMCID: PMC6429991 DOI: 10.1021/acs.chemmater.8b05361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/03/2019] [Indexed: 06/09/2023]
Abstract
Organic semiconducting crystals are characterized by anisotropic optical and electronic properties, which can be tailored by controlling the packing of the constituent molecules in the crystal unit cell. Here, the synthesis, structural characterization, and emission of anthracene derivatives are focused to correlate directed functionalization and optical properties. These compounds are easily and scalably prepared by standard synthesis techniques, and alterations in functional groups yield materials with either exclusive edge-to-face or face-to-face solid-state interactions. The resulting crystals feature either platelet or needle shapes, and the emission exhibits polarization ratios up to 5 at room temperature. In needle-shaped crystals, self-waveguiding of the emission is also observed with propagation loss coefficients as low as 1.3 dB mm-1. Moreover, optical coupling between crossing crystalline microwires is found and characterized. The combination of optical anisotropy and emission self-waveguiding opens interesting routes for the exploitation of these active materials in photonic applications, including optical integrated circuits and microscale light sources.
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Giannini C, Ladisa M, Lutz-Bueno V, Terzi A, Ramella M, Fusaro L, Altamura D, Siliqi D, Sibillano T, Diaz A, Boccafoschi F, Bunk O. X-ray scanning microscopies of microcalcifications in abdominal aortic and popliteal artery aneurysms. IUCRJ 2019; 6:267-276. [PMID: 30867924 PMCID: PMC6400185 DOI: 10.1107/s2052252519001544] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/28/2019] [Indexed: 05/27/2023]
Abstract
Abdominal aortic and popliteal artery aneurysms are vascular diseases which show massive degeneration, weakening of the vascular wall and loss of the vascular tissue functionality. They are driven by inflammatory, hemodynamical factors and biological alterations that may lead, in the case of an abdominal aortic aneurysm, to sudden and dangerous ruptures of the arteries. Here, human aortic and popliteal aneurysm tissues were obtained during surgical repair, and studied by synchrotron radiation X-ray scanning microdiffraction and small-angle scattering, to investigate the microcalcifications present in the tissues. Data collected during the experiments were transformed into quantitative microscopy images through the combination of statistical approaches and crystallographic methods. As a result of this multi-step analysis, microcalcifications, which are markers of the pathology, were classified in terms of chemical and structural content. This analysis helped to identify the presence of nanocrystalline hy-droxy-apatite and microcrystalline cholesterol, embedded in myofilament, and elastin-containing tissue with low collagen content in predominantly nanocrystalline areas. The generality of the approach allows it to be transferred to other types of tissue and other pathologies affected by microcalcifications, such as thyroid carcinoma, breast cancer, testicular microli-thia-sis or glioblastoma.
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Grisorio R, Di Clemente ME, Fanizza E, Allegretta I, Altamura D, Striccoli M, Terzano R, Giannini C, Irimia-Vladu M, Suranna GP. Exploring the surface chemistry of cesium lead halide perovskite nanocrystals. NANOSCALE 2019; 11:986-999. [PMID: 30569929 DOI: 10.1039/c8nr08011a] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Colloidal nanocrystals (NCs) of cesium lead halide perovskites (CsPbX3, X = Cl, Br or I) are emerging as an exciting class of optoelectronic materials, but the retention of their colloidal and structural integrity during isolation, purification and handling still represents a critical issue. The impelling questions concerning their intrinsic chemical instability are connected to the dynamic nature of the bonding between the inorganic surface and the long-chain capping ligands. However, the key aspects of CsPbX3's surface chemistry that directly impact their stability remain elusive. In this contribution, we provide an in-depth investigation of the surface properties of differently composed CsPbX3 NCs, prepared by traditional hot-injection methods. The study, mainly relying on solution NMR spectroscopy, is backed up by elemental analysis as well as morphological, structural and optical investigations. We ascertained that the nature of the ligand adsorption/desorption processes at the NC surface is dependent on its elemental composition, thus explaining the origin of the instability afflicting CsPbI3 NCs. We also evaluated the effect of NC purification as well as of the degradation pathways involving the organic shell on the surface chemistry of CsPbX3 NCs. This study paves the way for new post-functionalization strategies for this promising class of nanomaterials.
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Castelli A, Biffi G, Ceseracciu L, Spirito D, Prato M, Altamura D, Giannini C, Artyukhin S, Krahne R, Manna L, Arciniegas MP. Revealing Photoluminescence Modulation from Layered Halide Perovskite Microcrystals upon Cyclic Compression. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805608. [PMID: 30393907 DOI: 10.1002/adma.201805608] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/26/2018] [Indexed: 05/24/2023]
Abstract
Halide perovskites show promise for high-efficiency solar energy conversion and light-emitting diode devices owing to their bandgap, which falls within the visible optical range. However, due to their rigidity, GPa pressures are necessary to control the complex interplay between their electronic and crystallographic structure. Layered perovskites are likely to be controlled using much lower pressures by exploiting the optical anisotropy of the embedded organic molecules in the structure. This work introduces layered perovskite microplatelets and demonstrates the extreme sensitivity of their emission to cyclic mechanical loading in the range of tens of MPa. A drastic change in their emission is observed in situ, from near-white to an enhanced blue color. This process is reversible, as is evident from a hysteresis loop in the photoluminescence (PL) intensity of the microplatelets. A combination of experimental analysis and computational modelling shows that such behavior cannot be attributed to changes in the crystallographic structure of the flakes. Instead, it suggests that, thanks to their structural anisotropy, microplate alignment and reorientation are responsible for the observed PL modulation. The possibility to tune the optical emission of layered perovskite crystals via low pressures makes them highly interesting as active materials in applications where stress sensing or light modulation is desired.
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Gijsbers A, Montagut DC, Méndez-Godoy A, Altamura D, Saviano M, Siliqi D, Sánchez-Puig N. Interaction of the GTPase Elongation Factor Like-1 with the Shwachman-Diamond Syndrome Protein and Its Missense Mutations. Int J Mol Sci 2018; 19:E4012. [PMID: 30545121 PMCID: PMC6321010 DOI: 10.3390/ijms19124012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 12/06/2018] [Accepted: 12/08/2018] [Indexed: 12/14/2022] Open
Abstract
The Shwachman-Diamond Syndrome (SDS) is a disorder arising from mutations in the genes encoding for the Shwachman-Bodian-Diamond Syndrome (SBDS) protein and the GTPase known as Elongation Factor Like-1 (EFL1). Together, these proteins remove the anti-association factor eIF6 from the surface of the pre-60S ribosomal subunit to promote the formation of mature ribosomes. SBDS missense mutations can either destabilize the protein fold or affect surface epitopes. The molecular alterations resulting from the latter remain largely unknown, although some evidence suggest that binding to EFL1 may be affected. We further explored the effect of these SBDS mutations on the interaction with EFL1, and showed that all tested mutations disrupted the binding to EFL1. Binding was either severely weakened or almost abolished, depending on the assessed mutation. In higher eukaryotes, SBDS is essential for development, and lack of the protein results in early lethality. The existence of patients whose only source of SBDS consists of that with surface missense mutations highlights the importance of the interaction with EFL1 for their function. Additionally, we studied the interaction mechanism of the proteins in solution and demonstrated that binding consists of two independent and cooperative events, with domains 2⁻3 of SBDS directing the initial interaction with EFL1, followed by docking of domain 1. In solution, both proteins exhibited large flexibility and consisted of an ensemble of conformations, as demonstrated by Small Angle X-ray Scattering (SAXS) experiments.
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Diaferia C, Balasco N, Altamura D, Sibillano T, Gallo E, Roviello V, Giannini C, Morelli G, Vitagliano L, Accardo A. Assembly modes of hexaphenylalanine variants as function of the charge states of their terminal ends. SOFT MATTER 2018; 14:8219-8230. [PMID: 30265271 DOI: 10.1039/c8sm01441h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The ability of peptides to self-assemble represents a valuable tool for the development of biomaterials of biotechnological and/or biomedical interest. Diphenylalanine homodimer (FF) and its analogues are among the most promising systems in this field. The longest Phe-based building block hitherto characterized is pentaphenylalanine (F5). We studied the aggregation propensity and the structural/morphological features of assemblies of zwitterionic hexaphenylalanine H+-F6-O- and of three variants characterized by different charged states of the terminal ends (Ac-F6-Amide, H+-F6-Amide and Ac-F6-O-). As previously observed for PEGylated hexaphenylalanine (PEG8-F6), all F6 variants show a strong tendency to form β-rich assemblies in which the structural motif is constituted by antiparallel β-strands in the cross-β framework. Extensive replica exchange molecular dynamics simulations carried out on a pairs of F6 peptides indicate that the antiparallel β-structure of the final assemblies is likely dictated by the preferred association modes of the individual chains in the very early stages of the aggregation process. Our data suggest that even very small F6 peptides are properly pre-organized and prone to the build-up of the final assembly.
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Montes-de-Oca-Ávalos JM, Altamura D, Candal RJ, Scattarella F, Siliqi D, Giannini C, Herrera ML. Relationship between nano/micro structure and physical properties of TiO 2 -sodium caseinate composite films. Food Res Int 2018; 105:129-139. [DOI: 10.1016/j.foodres.2017.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 10/30/2017] [Accepted: 11/13/2017] [Indexed: 11/26/2022]
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Masi S, Aiello F, Listorti A, Balzano F, Altamura D, Giannini C, Caliandro R, Uccello-Barretta G, Rizzo A, Colella S. Connecting the solution chemistry of PbI 2 and MAI: a cyclodextrin-based supramolecular approach to the formation of hybrid halide perovskites. Chem Sci 2018; 9:3200-3208. [PMID: 29732103 PMCID: PMC5916222 DOI: 10.1039/c7sc05095j] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 02/12/2018] [Indexed: 11/29/2022] Open
Abstract
Cyclodextrin macrocycles are able to modify and control the solvation equilibria of hybrid perovskite components in solution by establishing supramolecular interactions.
The evolution from solvated precursors to hybrid halide perovskite films dictates most of the photophysical and optoelectronic properties of the final polycrystalline material. Specifically, the complex equilibria and the importantly different solubilities of lead iodide (PbI2) and methylammonium iodide (MAI) induce inhomogeneous crystal growth, often leading to a defect dense film showing non-optimal optoelectronic properties and intrinsic instability. Here, we explore a supramolecular approach based on the use of cyclodextrins (CDs) to modify the underlying solution chemistry. The peculiar phenomenon demonstrated is a tunable complexation between different CDs and MA+ cations concurrent to an out of cage PbI2 intercalation, representing the first report of a connection between the solvation equilibria of the two perovskite precursors. The optimal conditions in terms of CD cavity size and polarity translate to a neat enhancement of PbI2 solubility in the reaction media, leading to an equilibration of the availability of the precursors in solution. The macroscopic result of this is an improved nucleation process, leading to a perovskite material with higher crystallinity, better optical properties and improved moisture resistance. Remarkably, the use of CDs presents a great potential for a wide range of device-related applications, as well as for the development of tailored composite materials.
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Terzi A, Storelli E, Bettini S, Sibillano T, Altamura D, Salvatore L, Madaghiele M, Romano A, Siliqi D, Ladisa M, De Caro L, Quattrini A, Valli L, Sannino A, Giannini C. Effects of processing on structural, mechanical and biological properties of collagen-based substrates for regenerative medicine. Sci Rep 2018; 8:1429. [PMID: 29362434 PMCID: PMC5780384 DOI: 10.1038/s41598-018-19786-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/11/2017] [Indexed: 12/21/2022] Open
Abstract
The aim of this work was to investigate the structural features of type I collagen isoforms and collagen-based films at atomic and molecular scales, in order to evaluate whether and to what extent different protocols of slurry synthesis may change the protein structure and the final properties of the developed scaffolds. Wide Angle X-ray Scattering data on raw materials demonstrated the preferential orientation of collagen molecules in equine tendon-derived collagens, while randomly oriented molecules were found in bovine skin collagens, together with a lower crystalline degree, analyzed by the assessment of FWHM (Full Width at Half Maximum), and a certain degree of salt contamination. WAXS and FT-IR (Fourier Transform Infrared) analyses on bovine collagen-based films, showed that mechanical homogenization of slurry in acidic solution was the treatment ensuring a high content of super-organization of collagen into triple helices and a high crystalline domain into the material. In vitro tests on rat Schwannoma cells showed that Schwann cell differentiation into myelinating cells was dependent on the specific collagen film being used, and was found to be stimulated in case of homogenization-treated samples. Finally DHT/EDC crosslinking treatment was shown to affect mechanical stiffness of films depending on collagen source and processing conditions.
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Siliqi D, Sanchez-Puig N, Altamura D, Gijsbers A, Méndez-Godoy A, Giannini C, Saviano M. Inside structure of the EFL1, SBDS and their complex. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s2053273317089252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Diaferia C, Sibillano T, Altamura D, Roviello V, Vitagliano L, Giannini C, Morelli G, Accardo A. Structural Characterization of PEGylated Hexaphenylalanine Nanostructures Exhibiting Green Photoluminescence Emission. Chemistry 2017; 23:14039-14048. [PMID: 28782843 DOI: 10.1002/chem.201703055] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Indexed: 12/31/2022]
Abstract
Peptides containing aromatic residues are known to exhibit spontaneous phenomena of supramolecular organization into ordered nanostructures (NSs). In this work we studied the structural behavior and optoelectronic properties of new biocompatible materials obtained by the self-assembly of a series of hexaphenylalanines (F6) modified at the N terminus by a PEG chain of different lengths. PEG12 -F6, PEG18 -F6, and PEG24 -F6 peptides were synthesized by coupling sequentially two, three, or four units of amino-carboxy-PEG6 blocks, each one containing six oxyethylene repetitions. Changes in the length and composition of the PEG chain were found to modulate the structural organization of the phenylalanine-based nanostructures. An increase in the self-aggregation tendency was observed with longer PEG chains, whereas, independently of the PEG length, the peptide NSs display cross-β-like secondary structures with an antiparallel β-strand arrangement. WAXS/GIWAXS diffraction patterns indicate a progressive decrease in fiber order along the series. All the PEG-F6 derivatives present blue photoluminescent (PL) emission at 460 nm, with the adduct with the longest PEG chain (PEG24 -F6) showing an additional green emission at 530 nm.
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Epifani M, Kaciulis S, Mezzi A, Altamura D, Giannini C, Díaz R, Force C, Genç A, Arbiol J, Siciliano P, Comini E, Concina I. Corrigendum: Inorganic Photocatalytic Enhancement: Activated RhB Photodegradation by Surface Modification of SnO 2 Nanocrystals with V 2O 5-like species. Sci Rep 2017; 7:46855. [PMID: 28731461 PMCID: PMC5520769 DOI: 10.1038/srep46855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Epifani M, Kaciulis S, Mezzi A, Altamura D, Giannini C, Díaz R, Force C, Genç A, Arbiol J, Siciliano P, Comini E, Concina I. Inorganic Photocatalytic Enhancement: Activated RhB Photodegradation by Surface Modification of SnO 2 Nanocrystals with V 2O 5-like species. Sci Rep 2017; 7:44763. [PMID: 28300185 PMCID: PMC5353695 DOI: 10.1038/srep44763] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/13/2017] [Indexed: 11/09/2022] Open
Abstract
SnO2 nanocrystals were prepared by precipitation in dodecylamine at 100 °C, then they were reacted with vanadium chloromethoxide in oleic acid at 250 °C. The resulting materials were heat-treated at various temperatures up to 650 °C for thermal stabilization, chemical purification and for studying the overall structural transformations. From the crossed use of various characterization techniques, it emerged that the as-prepared materials were constituted by cassiterite SnO2 nanocrystals with a surface modified by isolated V(IV) oxide species. After heat-treatment at 400 °C, the SnO2 nanocrystals were wrapped by layers composed of vanadium oxide (IV-V mixed oxidation state) and carbon residuals. After heating at 500 °C, only SnO2 cassiterite nanocrystals were obtained, with a mean size of 2.8 nm and wrapped by only V2O5-like species. The samples heat-treated at 500 °C were tested as RhB photodegradation catalysts. At 10-7 M concentration, all RhB was degraded within 1 h of reaction, at a much faster rate than all pure SnO2 materials reported until now.
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Camposeo A, Pensack RD, Moffa M, Fasano V, Altamura D, Giannini C, Pisignano D, Scholes GD. Anisotropic Conjugated Polymer Chain Conformation Tailors the Energy Migration in Nanofibers. J Am Chem Soc 2016; 138:15497-15505. [PMID: 27933935 PMCID: PMC5133673 DOI: 10.1021/jacs.6b10761] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Indexed: 01/22/2023]
Abstract
Conjugated polymers are complex multichromophore systems, with emission properties strongly dependent on the electronic energy transfer through active subunits. Although the packing of the conjugated chains in the solid state is known to be a key factor to tailor the electronic energy transfer and the resulting optical properties, most of the current solution-based processing methods do not allow for effectively controlling the molecular order, thus making the full unveiling of energy transfer mechanisms very complex. Here we report on conjugated polymer fibers with tailored internal molecular order, leading to a significant enhancement of the emission quantum yield. Steady state and femtosecond time-resolved polarized spectroscopies evidence that excitation is directed toward those chromophores oriented along the fiber axis, on a typical time scale of picoseconds. These aligned and more extended chromophores, resulting from the high stretching rate and electric field applied during the fiber spinning process, lead to improved emission properties. Conjugated polymer fibers are relevant to develop optoelectronic plastic devices with enhanced and anisotropic properties.
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Giannini C, Altamura D, Siliqi D, Sibillano T, Caro LD, Pastore S, Ladisa M. X-ray scattering–based studies of nano/bio-structures with hierarchical order for nanomedicine applications. Acta Crystallogr A Found Adv 2016. [DOI: 10.1107/s2053273316093980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Siliqi D, Altamura D, Gijsbers A, de la Mora E, Giannini C, Sibillano T, Saviano M, Sanchez-Puig N. Small-angle X-ray scattering (SAXS) studies of the low-resolution structure of the ribosomal GTPase EFL1, the SBDS protein and their complex. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2016. [DOI: 10.1107/s2053273316097308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sibillano T, De Caro L, Scattarella F, Scarcelli G, Siliqi D, Altamura D, Liebi M, Ladisa M, Bunk O, Giannini C. Interfibrillar packing of bovine cornea by table-top and synchrotron scanning SAXS microscopy. J Appl Crystallogr 2016; 49:1231-1239. [PMID: 27504077 PMCID: PMC4970496 DOI: 10.1107/s1600576716010396] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/27/2016] [Indexed: 11/10/2022] Open
Abstract
Bovine cornea was studied with scanning small-angle X-ray scattering (SAXS) microscopy, by using both synchrotron radiation and a microfocus laboratory source. A combination of statistical (adaptive binning and canonical correlation analysis) and crystallographic (pair distribution function analysis) approaches allowed inspection of the collagen lateral packing of the supramolecular structure. Results reveal (i) a decrease of the interfibrillar distance and of the shell thickness around the fibrils from the periphery to the center of the cornea, (ii) a uniform fibril diameter across the explored area, and (iii) a distorted quasi-hexagonal arrangement of the collagen fibrils. The results are in agreement with existing literature. The overlap between laboratory and synchrotron-radiation data opens new perspectives for further studies on collagen-based/engineered tissues by the SAXS microscopy technique at laboratory-scale facilities.
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Siliqi D, De Caro L, Ladisa M, Scattarella F, Mazzone A, Altamura D, Sibillano T, Giannini C. SUNBIM: a package for X-ray imaging of nano- and biomaterials using SAXS, WAXS, GISAXS and GIWAXS techniques. J Appl Crystallogr 2016. [DOI: 10.1107/s1600576716006932] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SUNBIM(supramolecular and submolecular nano- and biomaterials X-ray imaging) is a suite of integrated programs which, through a user-friendly graphical user interface, are optimized to perform the following: (i)q-scale calibration and two-dimensional → one-dimensional folding on small- and wide-angle X-ray scattering (SAXS/WAXS) and grazing-incidence SAXS/WAXS (GISAXS/GIWAXS) data, also including possible eccentricity corrections for WAXS/GIWAXS data; (ii) background evaluation and subtraction, denoising, and deconvolution of the primary beam angular divergence on SAXS/GISAXS profiles; (iii) indexing of two-dimensional GISAXS frames and extraction of one-dimensional GISAXS profiles along specific cuts; (iv) scanning microscopy in absorption and SAXS contrast. The latter includes collection of transmission and SAXS data, respectively, in a mesh across a mm2area, organization of the as-collected data into a single composite image of transmission values or two-dimensional SAXS frames, analysis of the composed data to derive the absorption map and/or the spatial distribution, and orientation of nanoscale structures over the scanned area.
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Altamura D, Pastore SG, Raucci MG, Siliqi D, De Pascalis F, Nacucchi M, Ambrosio L, Giannini C. Scanning Small- and Wide-Angle X-ray Scattering Microscopy Selectively Probes HA Content in Gelatin/Hydroxyapatite Scaffolds for Osteochondral Defect Repair. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8728-8736. [PMID: 27020229 DOI: 10.1021/acsami.6b00557] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This study is aimed at investigating the structure of a scaffold made of bovine gelatin and hydroxyapatite for bone tissue engineering purposes. In particular, the detailed characterization of such a material has a great relevance because of its application in the healing process of the osteochondral defect that consists of a damage of cartilage and injury of the adjacent subchondral bone, significantly compromising millions of patient's quality of life. Two different techniques exploiting X-ray radiation, with table-top setups, are used: microtomography (micro-CT) and microdiffraction. Micro-CT characterizes the microstructure in the three dimensions at the micrometer scale spatial resolution, whereas microdiffraction provides combined structural/morphological information at the atomic and nanoscale, in two dimensional microscopy images with a hundred micrometer spatial resolution. The combination of these two techniques allowed an appropriate structural characterization for the purpose of validating the engineering approach used for the realization of the hydroxyapatite gradient across the scaffold, with properties close to the natural model.
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De Caro L, Altamura D, Arciniegas M, Siliqi D, Kim MR, Sibillano T, Manna L, Giannini C. Ptychographic Imaging of Branched Colloidal Nanocrystals Embedded in Free-Standing Thick Polystyrene Films. Sci Rep 2016; 6:19397. [PMID: 26775682 PMCID: PMC4726119 DOI: 10.1038/srep19397] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 12/07/2015] [Indexed: 12/30/2022] Open
Abstract
Research on composite materials is facing, among others, the challenging task of incorporating nanocrystals, and their superstructures, in polymer matrices. Electron microscopy can typically image nanometre-scale structures embedded in thin polymer films, but not in films that are micron size thick. Here, X-ray Ptychography was used to visualize, with a resolution of a few tens of nanometers, how CdSe/CdS octapod-shaped nanocrystals self-assemble in polystyrene films of 24 ± 4 μm, providing a unique means for non-destructive investigation of nanoparticles distribution and organization in thick polymer films.
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Siliqi D, Sanchez-Puig N, de la Mora E, Méndez-Godoy A, Altamura D, Giannini C, Sibillano T, Saviano M. Studies of the conformational changes on the ribosomal GTPase EFL1 using SAXS. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315096175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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