128 research outputs found
Composition and morphology effects on catalase mimetic activity ofpotential bioactive glasses
Cell Proliferation to Evaluate Preliminarily the Presence of Enduring Self-Regenerative Antioxidant Activity in Cerium Doped Bioactive Glasses
(1) Background: a cell evaluation focused to verify the self-regenerative antioxidant activity is performed on cerium doped bioactive glasses. (2) Methods: the glasses based on 45S5 Bioglass®, are doped with 1.2 mol%, 3.6 mol% and 5.3 mol% of CeO2 and possess a polyhedral shape (~500 µm2). Glasses with this composition inhibit oxidative stress by mimicking catalase enzyme (CAT) and superoxide dismutase (SOD) activities; moreover, our previous cytocompatibility tests (neutral red (NR), 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Bromo-2-deoxyUridine (BrdU)) reveal that the presence of cerium promotes the absorption and vitality of the cells. The same cytocompatibility tests were performed and repeated, in two different periods (named first and second use), separated from each other by four months. (3) Results: in the first and second use, NR tests indicate that the presence of cerium promotes once again cell uptake and viability, especially after 72 h. A decrease in cell proliferation it is observed after MTT and BrdU tests only in the second use. These findings are supported by statistically significant results (4) Conclusions: these glasses show enhanced proliferation, both in the short and in the long term, and for the first time such large dimensions are studied for this kind of study. A future prospective is the implantation of these bioactive glasses as bone substitute in animal models
Biostimulants derived from organic urban wastes and biomasses: An innovative approach
We used humic and fulvic acids extracted from digestate to formulate nanohybrids with potential applications in agronomy. In order to obtain a synergic co-release of plant-beneficial agents, we functionalized with humic substances two inorganic matrixes: hydroxyapatite (Ca10(PO4)6(OH)2, HP) and silica (SiO2) nanoparticles (NPs). The former is a potential controlled-release fertilizer of P, and the latter has a beneficial effect on soil and plants. SiO2 NPs are obtained from rice husks by a reproducible and fast procedure, but their ability to absorb humic substances is very limited. HP NPs coated with fulvic acid are instead a very promising candidate, based on desorption and dilution studies. The different dissolutions observed for HP NPs coated with fulvic and humic acids could be related to the different interaction mechanisms, as suggested by the FT-IR study
Ce-MBGs Loaded with Gentamicin: Characterization and In Vitro Evaluation
Mesoporous Bioactive Glasses (MBGs) are biomaterials widely used in tissue engineering, particularly for hard tissue regeneration. One of the most frequent postoperative complications following a biomaterial surgical implant is a bacterial infection, which usually requires treatment by the systemic administration of drugs (e.g., antibiotics). In order to develop biomaterials with antibiotic properties, we investigated cerium-doped MBGs (Ce-MBGs) as in situ-controlled drug delivery systems (DDSs) of gentamicin (Gen), a wide spectrum antibiotic commonly employed against bacteria responsible of postoperative infections. Here we report the optimization of Gen loading on MBGs and the evaluation of the antibacterial properties and of retention of bioactivity and antioxidant properties of the resulting materials. The Gen loading (up to 7%) was found to be independent from cerium content, and the optimized Gen-loaded Ce-MBGs retain significant bioactivity and antioxidant properties. The antibacterial efficacy was verified up to 10 days of controlled release. These properties make Gen-loaded Ce-MBGs interesting candidates for simultaneous hard tissue regeneration and in situ antibiotic release
Crystal structure of a new homochiral one-dimensional zincophosphate containing L-methionine
catena-Poly[[(L-methionine-[kappa]O)zinc]-[mu]3-(hydrogen phosphato)-[kappa]3O:O':O''], [Zn{PO3(OH)}(C5H11NO2S)]n, a new one-dimensional homochiral zincophosphate, was hydrothermally synthesized using L-methionine as a structure-directing agent. The compound consists of a network of ZnO4 and (HO)PO3 tetrahedra that form ladder-like chains of edge-fused Zn2P2O4 rings propagating parallel to [100]. The chains are decorated on each side by zwitterionic L-methionine ligands, which interact with the inorganic framework via Zn-O coordination bonds. The structure displays interchain N-H...O and O-H...S hydrogen bonds
Towards the controlled release of metal nanoparticles frombiomaterials: Physico-chemical, morphological and bioactivityfeatures of Cu-containing sol–gel glasses
Preparation and Luminescence Properties of Ba5Si8O21 Long Persistent Phosphors Doped with Rare-Earth Elements
The phosphors of formula Ba5Si8O21:Eu2+,Dy3+ were synthesized and studied in order
to improve their properties. Their synthesis conditions were evaluated as a function of precursors,
crucible composition, flux agents, dopants and temperatures. The samples were characterised by
means of a systematic investigation through elemental, kinetic, mineralogical (both qualitative and
quantitative), and morphological analysis. This study allows for a careful evaluation of the parameters
that influence the formation and properties of Ba5Si8O21:Eu2+,Dy3+ phosphors. As for the synthesis
conditions, the use of Na2SiO3, BaCO3 and NH4Cl as precursors was very important to reduce
the temperature and time of synthesis. The reducing atmosphere produced with purified coal was
cheaper and gave results similar to the more traditional gas mixture (H2/N2). At the end of this study,
a phosphor with improved long persistent phosphorescence (LPP) characteristics was obtained with
Ba/Si = 0.7, Eu/Si = 2.8
7 10 123 and Dy/Si = 3.6
7 10 123
following a 6 h-synthesis in a quartz crucibl
SiO2-CaO-P2O5 bioactive glasses: A promising curcuminoids delivery system
In this paper, we report the study of the loading and the release of curcuminoids by bioactive glasses (BG) and mesoporous bioactive glasses (MBG). Through a detailed spectroscopic study, it was possible to determine the amount and the type of molecules released in water and in simulated body fluid (SBF). In particular, curcumin and K2T21 show a good ability to be released in di-keto and keto-enolic form, depending from the pH. However, after 24 h, the amount of pristine curcumin release is very low with a consequent increment of degradation products derived by curcuminoids. The presence of -OH groups on curcuminoids is a fundamental pre-requisite in order to obtain a high loading and release in polar solution such as water and SBF. The substrate on which we loaded the drugs does not seem to affect significantly the loading and the release of the drugs. The environment, instead, affects the release: for all the drugs, the release in SBF, buffered at pH of 7.4, is slightly worse than the release in water (basic pH values)
Conjugation of amino-bioactive glasses with 5-aminofluorescein as probe molecule for the development of pH sensitive stimuli-responsive biomaterials
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