Biomimetic hybrid scaffolds for osteo-chondral tissue repair: Design and osteogenic differentiation of human placenta-derived cells (hPDC)

A novel functionally-graded hybrid (FGHY) scaffold was designed and developed with a load-bearing structure represented by a PU foam loaded with a graded composition of CaPs (biomimetic component) and pectin gel as cell carrier. hPDC populations encapsulated in pectin gels and injected into the FGHY scaffolds demonstrated the ability to differentiate toward the osteogenic lineage. The ability of these biomimetic hybrid scaffolds to stimulate cell adhesion and proliferation and to support differentiation of hPDCs make these scaffolds excellent candidates for an use in bone regeneratio

Polyurethane foam/nano hydroxyapatite composite as a suitable scaffold for bone tissue regeneration

In bone tissue regeneration, the use of biomineralized scaffolds to create the 3D porous structure needed for well-fitting with defect size and appropriate cell interactions, is a promising alternative to autologous and heterologous bone grafts. Biomineralized polyurethane (PU) foams are here investigated as scaffold for bone tissue regeneration. Biomineralization of the foams was carried out by activation of PU surface by a two steps procedure performed for different times (1 to 4 weeks). Scaffolds were investigated for morphological, chemico-physical and mechanical properties, as well as for in vitro interaction with rat Bone Marrow Mesenchymal Stem Cells (BMSCs). Untreated and biomineralized PU samples showed a homogenous morphology and regular pore size (average Ã\u98 = 407 μm). Phase and structure of formed calcium phosphates (CaPs) layer onto the PU foam were analyzed by Fourier Transform Infrared spectroscopy and X-ray diffraction, proving the formation of bone-like nano hydroxyapatite. Biomineralization caused a significant increase of mechanical properties of treated foams compared to untreated ones. Biomineralization also affected the PU scaffold cytocompatibility providing a more appropriate surface for cell attachment and proliferation. Considering the obtained results, the proposed scaffold can be considered suitable for bone tissue regeneration

Interaction of vanadium species with a functionalized graphite electrode: A combined theoretical and experimental study for flow battery applications

Vanadium redox flow battery (VRFB) is one of the most promising large-scale energy storage system; however, a widespread VRFB development is still limited by the poor electrochemical activity of graphite electrodes and a poor understanding of redox reactions occurring at electrode/electrolyte interface. In this work, DFT was performed to study the first solvation shell structure of all vanadium ions and to investigate the reactivity of modified graphite electrodes toward the V 2+ /V 3+ redox species. The results suggest that the presence of oxygen and nitrogen functionalities at the electrode edges provides more active sites for adsorption of the V 2+ /V 3+ redox couple, and therefore improve electron transfer kinetics. These results have been experimentally validated by means of Cyclic Voltammetry and Electrochemical Impedance Spectroscopy with carbon black electrode having different density of oxygen and nitrogen-containing surface groups. © 2019 Elsevier B.V

Electrochemical and spectroscopic study of vanadyl acetylacetonate–ionic liquids interactions

A panel of ionic liquids has been synthesized and their effect on the vanadyl acetylacetonate solubility in acetonitrile has been firstly assessed. 1-Butyl-3-methylimidazolium acetate showed an unprecedented result, increasing the VO(acac)2 solubility in acetonitrile of more than one magnitude order (from 0.06 M to 1.1 M) opening new interesting horizons for the possible applications of this vanadium complex. The electrochemical effect of the considered ionic liquids has been subsequently investigated through cyclic voltammetry and linear sweep voltammetry with rotating disk electrode, determining diffusion coefficient and kinetic current of VO(acac)2 in the considered media. In order to achieve a deeper understanding on the examined systems, VO(acac)2 solutions in acetonitrile ILs were eventually studied through IR, UV– vis, and EPR spectroscopies, finding evidences, corroborated by DFT studies, of the formation of strong adducts between VO(acac)2 and ILs