Electrophoretic deposition of composite coatings based on alginate matrix/45S5 bioactive glass particles doped with B, Zn or Sr

In this research work composite coatings made of alginate and 45S5 bioactive glass particles doped with B, Zn or Sr were synthesized by means of electrophoretic deposition and characterized from morphological, compositional, thermogravimetric, mechanical and electrochemical points of view. The developed coatings were also subjected to in vitro test in SBF solution to evaluate their ability to induce hydroxyapatite precipitation and cytocompatibility evaluation using human primary fibroblasts. The obtained results demonstrated a good homogeneity of the coatings, high adhesion and a protective behavior towards the substrate. The thermogravimetric analysis proved that the glass amount was constant before and after the deposition and all the investigated coatings promoted the deposition of hydroxyapatite but with different kinetics. Since the Zn containing coating showed the best bioactive behavior it was subjected to cytocompatibility test, which demonstrated, after an initial reduction of cell viability, a good cell proliferation and the production of collagen from the ECM. These findings suggest that the obtained coatings are promising materials to coat metallic prosthetic devices

Surface Functionalization of a Silica-Based Bioactive Glass with Compounds from Rosa canina Bud Extracts

Bud extracts are a new category of vegetal products, which are used in gemmotherapy. These products are liquid preparation sources of bioactive molecules (phytochemicals) and are used in medicine as health-promoting agents. Rosa canina is a medicinal plant belonging to the family Rosaceae. The R. canina bud extracts, in particular, possess anti-inflammatory and antioxidant activities due to the presence of flavonoids and other phenolic compounds. The combination of R. canina bud extracts with biomaterials can be promising for obtaining multifunctional materials carrying both inorganic and biological properties. In this work, a protocol of functionalization has been properly designed, for the first time in the literature, in order to graft various bud extracts of R. canina to a silica-based bioactive glass (CEL2). The Folin-Ciocalteu method was used to determine the redox capacity of total polyphenols in the extracts and on functionalized solid samples. X-ray photoelectron spectroscopy analysis and fluorescence microscopy were employed to investigate the presence of phenol substances on the material surface. Bioactivity (in terms of ability of inducing hydroxyapatite precipitation) has been investigated by soaking the samples, with or without functionalization, in simulated body fluid. The presence of the polyphenols from bud extracts not only preserved glass bioactivity but even enhanced it. In particular, the solution obtained from the byproducts of primary extraction in glycerol macerate showed the best performances. Moreover, the presence and antioxidant activity of bud extract compounds on the material surface after grafting demonstrate the possibility of combining the glass inorganic bioactivity with the biomolecule-specific properties, making possible a local action at the implant site. The promising results reported in this work pave the way for the realization of new multifunctional materials with a green approach