G. Iucci

Driving h‐osteoblast adhesion and proliferation on titania: peptide hydrogels decorated with growth factors and adhesive conjugates

Hydrogels from self‐assembling ionic complementary peptides have been receiving much interest from the scientific community as mimetics of the extracellular matrix that can offer three‐dimensional support for cell growth or become vehicles for the delivery of stem cells or drugs. These scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In order to develop a novel bioactive titanium implant, we propose the introduction of a layer of ionic‐complementary self‐assembling peptides (EAbuK) on Ti whose surface has been previously sandblasted and acid etched. The peptide layer is anchored to the metal by covalent functionalization of titania with self‐assembling sequences. The peptide layer has also been enriched by the insulin‐like growth factor‐1 incorporated to the layer and/or a conjugate obtained by chemoselective ligation between EAbuK and a sequence of 25 residues containing four GRGDSP motifs per chain. X‐ray photoelectron spectroscopy studies confirmed a change in the surface composition in agreement with the proposed decorations. An evaluation of the contact angle showed a substantial change in wettability induced by the peptide layer. The human osteoblast adhesion and proliferation assays showed an increase in adhesion for the surfaces enriched with conjugate at a concentration of 3.8u2009×u200910−7u2009m and an enhanced proliferation for samples enriched with insulin‐like growth factor‐1 at the highest concentration tested (2.1u2009×u200910−5u2009m). Copyright

Ni supported on YSZ: XAS and XPS characterization and catalytic activity for CO2 methanation

Ni supported on yttrium-stabilized zirconium oxide catalysts have been prepared by electroless plating method. Structure, electronic and chemical state of Ni as a function of Ni content (1, 7 and 12xa0wt%) have been characterized combining X-ray diffraction, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction (H2-TPR) and BET. The catalytic activity for the CO2 methanation was studied in the 250–500xa0°C temperature range, finding the highest CO2 conversion and CH4 selectivity for the catalyst with the largest Ni loading. A dependence of activity and CH4 selectivity on Ni crystallites size was highlighted.

XPS investigation on the structure of two dipeptides studied as models of self-assembling oligopeptides: comparison between experiments and theory

The adsorption on TiO2 surface of two dipeptides AE (L-alanine-L-glutamic acid) and AK (L-alanine-L-lysine), that are building blocks of the more complex self-complementary amphiphilic oligopeptides and are therefore a good model in the interpretation of the complex peptide spectra, has been investigated both theoretically and experimentally. The chemical structure and composition of thin films of both dipeptides on TiO2 were investigated by XPS (X-ray photoelectron spectroscopy). Theoretical ab-initio calculations (ΔSCF) were also performed to simulate the spectra allowing a direct comparison between experiment and theory.

Covalent grafting of Ti surfaces with peptide hydrogel decorated with growth factors and self-assembling adhesive sequences

Hydrogels from self‐assembling ionic complementary peptides have been receiving much interest from the scientific community as mimetics of the extracellular matrix that can offer three‐dimensional support for cell growth or become vehicles for the delivery of stem cells or drugs. These scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In order to develop a novel bioactive titanium implant, we propose the introduction of a layer of ionic‐complementary self‐assembling peptides (EAbuK) on Ti whose surface has been previously sandblasted and acid etched. The peptide layer is anchored to the metal by covalent functionalization of titania with self‐assembling sequences. The peptide layer has also been enriched by the insulin‐like growth factor‐1 incorporated to the layer and/or a conjugate obtained by chemoselective ligation between EAbuK and a sequence of 25 residues containing four GRGDSP motifs per chain. X‐ray photoelectron spectroscopy studies confirmed a change in the surface composition in agreement with the proposed decorations. An evaluation of the contact angle showed a substantial change in wettability induced by the peptide layer. The human osteoblast adhesion and proliferation assays showed an increase in adhesion for the surfaces enriched with conjugate at a concentration of 3.8u2009×u200910−7u2009m and an enhanced proliferation for samples enriched with insulin‐like growth factor‐1 at the highest concentration tested (2.1u2009×u200910−5u2009m). Copyright

Biofunctionalization of TiO 2 surfaces with self-assembling oligopeptides in different pH and Ionic Strength conditions: Charge effects and molecular organization

Self-assembling peptides (SAPs) were investigated by means of XPS and Angular Dependent NEXAFS spectroscopies, with the aim to probe the influence of pH and Ionic Strength conditions on the chemical structure and molecular organization of SAPs anchored on titania surfaces. XPS at the C1s, N1s, O1s core levels allowed to study surfaces and biomolecule/substrate interfaces. NEXAFS data allowed ascertaining that SAPs molecular structure is preserved upon grafting to the titania surface. Angular Dependent NEXAFS was used to investigate the influence of environmental conditions on the molecular organization behaviour. The objective of our study was to establish a set of methodologies for obtaining arrangements of well-organized biomolecules on scaffolds surfaces as a basic technology to develop and optimize cells adhesion and proliferation for tissue engineering applications.

Driving h-osteoblast adhesion and proliferation on titania: peptide hydrogels decorated with growth factors and adhesive conjugates: DRIVING H-OSTEOBLAST ADHESION AND PROLIFERATION ON TITANIA

Hydrogels from self‐assembling ionic complementary peptides have been receiving much interest from the scientific community as mimetics of the extracellular matrix that can offer three‐dimensional support for cell growth or become vehicles for the delivery of stem cells or drugs. These scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In order to develop a novel bioactive titanium implant, we propose the introduction of a layer of ionic‐complementary self‐assembling peptides (EAbuK) on Ti whose surface has been previously sandblasted and acid etched. The peptide layer is anchored to the metal by covalent functionalization of titania with self‐assembling sequences. The peptide layer has also been enriched by the insulin‐like growth factor‐1 incorporated to the layer and/or a conjugate obtained by chemoselective ligation between EAbuK and a sequence of 25 residues containing four GRGDSP motifs per chain. X‐ray photoelectron spectroscopy studies confirmed a change in the surface composition in agreement with the proposed decorations. An evaluation of the contact angle showed a substantial change in wettability induced by the peptide layer. The human osteoblast adhesion and proliferation assays showed an increase in adhesion for the surfaces enriched with conjugate at a concentration of 3.8u2009×u200910−7u2009m and an enhanced proliferation for samples enriched with insulin‐like growth factor‐1 at the highest concentration tested (2.1u2009×u200910−5u2009m). Copyright