ArcAdiA

Assessment of novel chemical strategies for covalent attachment of adhesive peptides to rough titanium surfaces: XPS analysis and biological evaluation

Sat, 31 Oct 2009 23:00:00 GMT

Assessment of novel chemical strategies for covalent attachment of adhesive peptides to rough titanium surfaces: XPS analysis and biological evaluation Dettin, Monica; Thushari, Herat; Gambaretto, Roberta; Iucci, Giovanna; Battocchio, Chiara; Bagno, Andrea; Ghezzo, Francesca; Di Bello, Carlo; Polzonetti, Giovanni; Di Silvio, Lucy 2009-11 Journal of Biomedical Materials Research A 91A 463-479 Bioactive molecules have been proposed to promote beneficial interactions at bone-implant interfaces for enhancing integration. The main objective of this study was to develop novel methods to functionalize oxidized titanium surfaces by the covalent immobilization of bioactive peptides, through selective reaction involving single functional groups. In the first protocol, an aminoalkylsilane was covalently linked to the Ti oxide layer, followed by covalent binding of glutaric anhydride to the free NH2 groups. The carboxylic group Of glutaric anhydride was used to condense the free N-terminal group of the side-chain protected peptide sequence. Finally, the Surface was treated with trifluoroacetic acid to deprotect side-chain groups. In the second protocol, the peptide was directly anchored to the Ti oxide surface via UV activation of an arylazide peptide analogue. X-ray photoelectron spectroscopy analyses confirmed that modifications induced onto surface composition were in agreement with the reactions performed. The peptide density of each biomimetic Surface was determined on the basis of radiolabeling and XPS derived reaction yields. The in vitro cellular response of the biomimetic surfaces was evaluated using a primary human osteoblast cell model. Cell adhesion, proliferation, differentiation, and mineralization were examined at initial-, short-, and long-time periods. In was shown that the biomimetic surface obtained through photoprobe-marked analogue that combines an easily-performed modification provides a favorable surface for an enhanced cellular response. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 91A: 463-479, 200

Self-Assembled Monolayers Based on Pd-Containing Organometallic Thiols:Preparation and Structural Characterization

Fri, 31 Jul 2009 22:00:00 GMT

Self-Assembled Monolayers Based on Pd-Containing Organometallic Thiols:Preparation and Structural Characterization Vitaliano, Rosa; Fratoddi, Ilaria; Venditti, Iole; Roviello, Giuseppina; Battocchio, Chiara; Polzonetti, Giovanni; Russo, Maria Vittoria 2009-08 The Journal of phisical chemistry A 113 14730–14740 Multilayers and self-assembled monolayers of on-purpose-preparedorganometallic thiolates, trans-[Pd(PBu3)(2)(SCOCH3)(2)], trans-[(C6H5CC)Pd(PBu3)(2)(SCOCH3)], and trans, trans-[(CH3COS)Pd(PBu3)(2)-(CC-C6H4-C6H4-C C)(PBu3)(2)Pd(SCOCH3)] Were deposited onto goldsurfaces. High-resolution X-ray photoelectron spectroscopy andnear-edge X-ray absorption fine structure measurements allowed us toassess the anchoring of the organometallic thiols onto gold substrates;the interaction occurring at the interface; and their molecularorientation oil the surface with tilt angles of about 30 degrees-40degrees, depending on. the investigated molecule. The molecule packingdensity/coverage was also assessed.

Palladium nanoparticles supported on polyvinylpyridine: Catalyticactivity in Heck-type reactions and XPS structural studies

Sat, 28 Feb 2009 23:00:00 GMT

Palladium nanoparticles supported on polyvinylpyridine: Catalyticactivity in Heck-type reactions and XPS structural studies Evangelisti, Claudio; Panziera, Nicoletta; Pertici, Paolo; Vitulli, Giovanni; Salvadori, Piero; Battocchio, Chiara; Polzonetti, Giovanni 2009-03 Journal of catalysis 262 287-293 Palladium nanoparticles, obtained by metal vapour synthesis (MVS), weredeposited on cross-linked polyvinylpyridine. The Pd/PVPy system showedhigh catalytic activity in the Heck C-C coupling reaction of iodo- andbromo-arenes (iodobenzene, bromobenzene, p-nitrobromobenzene,p-bromoacetophenone, p-(methoxy)bromobenzene) with alkyl acrylates(methyl acrylate, n-butyl acrylate, ethylhexyltrans-3-(4-methoxyphenyl)acrylate) at 100 degrees C-175 degrees Cworking under nitrogen atmosphere as well as in air. The catalyst isstable and the leaching of metal in solution is very low. When reused,the recovered Pd/PVPy maintains the catalytic activity of the pristinematerial. XPS structural studies performed on the starting catalyst aswell as on the recovered one indicate the presence of a interactionbetween the basic nitrogen of the pyridine present in the polymer andthe metal. (C) 2009 Elsevier Inc. All rights reserved.

Assessment of novel chemical strategies for covalent attachment ofadhesive peptides to rough titanium surfaces: XPS analysis andbiological evaluation

Sat, 31 Oct 2009 23:00:00 GMT

Assessment of novel chemical strategies for covalent attachment ofadhesive peptides to rough titanium surfaces: XPS analysis andbiological evaluation Dettin, Monica; Herath, Thushari; Gambaretto, Roberta; Iucci, Giovanna; Battocchio, Chiara; Bagno, Andrea; Ghezzo, Francesca; Di Bello, Carlo; Polzonetti, Giovanni; Di Silvio, Lucy 2009-11 Journal of biomedical materials research 91A 463-479 Bioactive molecules have been proposed to promote beneficialinteractions at bone-implant interfaces for enhancing integration. Themain objective of this study was to develop novel methods tofunctionalize oxidized titanium surfaces by the covalent immobilizationof bioactive peptides, through selective reaction involving singlefunctional groups. In the first protocol, an aminoalkylsilane wascovalently linked to the Ti oxide layer, followed by covalent bindingof glutaric anhydride to the free NH2 groups. The carboxylic group Ofglutaric anhydride was used to condense the free N-terminal group ofthe side-chain protected peptide sequence. Finally, the Surface wastreated with trifluoroacetic acid to deprotect side-chain groups. Inthe second protocol, the peptide was directly anchored to the Ti oxidesurface via UV activation of an arylazide peptide analogue. X-rayphotoelectron spectroscopy analyses confirmed that modificationsinduced onto surface composition were in agreement with the reactionsperformed. The peptide density of each biomimetic Surface wasdetermined on the basis of radiolabeling and XPS derived reactionyields. The in vitro cellular response of the biomimetic surfaces wasevaluated using a primary human osteoblast cell model. Cell adhesion,proliferation, differentiation, and mineralization were examined atinitial-, short-, and long-time periods. In was shown that thebiomimetic surface obtained through photoprobe-marked analogue thatcombines an easily-performed modification provides a favorable surfacefor an enhanced cellular response. (C) 2008 Wiley Periodicals, Inc. JBiomed Mater Res 91A: 463-479, 2009

Hydrothermal N-doped TiO2: Explaining photocatalytic properties by electronic and magnetic identification of N active sites

Tue, 24 Nov 2009 23:00:00 GMT

Hydrothermal N-doped TiO2: Explaining photocatalytic properties by electronic and magnetic identification of N active sites D’Arienzo, Massimiliano; Scotti, Roberto; Wahba, Laura; Battocchio, Chiara; Bemporad, Edoardo; Nale, Angeloclaudio; Morazzoni, Franca 2009-11-25 Applied Catalysis. B, Environmental 93 149–155 N-doped TiO2 nanocrystals with high photoactivity in the visible range, were successfully synthesized by hydrothermal method, followed by thermal annealing at different temperatures (350–600 8C), in order to allow differential nitrogen diffusion into the TiO2 lattice. Optical and magnetic properties, studied by diffuse reflectance spectroscopy, electron paramagnetic resonance and X-ray photoelectron spectroscopy analysis, revealed that TiO2 was effectively doped. The thermal treatment induces insertion of nitrogen into TiO2 lattice in the form of nitride anion NÀ, detected as N by EPR, whose ionic character varies with the temperature of annealing. The amount of N increases till 450 8C, then it decreases. Similar trend was observed for the photomineralization of phenol under visible light irradiation (l > 385 nm): the photoactivity of N-doped samples becomes maximum for N–TiO2 annealed at 450 8C. The overall results suggest that the efficacy of the catalyst depends on the ability of NÀ centers to trap photogenerated holes. This effect lowers the rate of electron–hole recombination and allows the N (NÀ + h+) center acts as strong oxidizing agent.