Early stage reactivity and in vitro behavior of silica-based bioactive glasses and glass-ceramics.
The surface reactivity of different sets of glasses and glass-ceramics belonging to the SiO(2)-P(2)O(5)-CaO-MgO-K(2)O-Na(2)O system have been investigated. The attention was focused on the role of their composition on the bioactivity kinetics, in terms of pH modifications, silica-gel formation and its evolution toward hydroxycarbonatoapatite, after different times of soaking in simulated body fluid. Glasses and glass ceramics have been characterized by thermal analysis, SEM-EDS observations and phase analysis (XRD). XPS measurements have been carried out on the most representative set of sample in order to evaluate the evolution of the surface species during the growth of silica-gel and hydroxycarbonatoapatite. The response of murine fibroblast 3T3 to the material before and after a conditioning pre-treatment (immersion in SBF) has been investigated on the same set of samples in order to point out the role of the bioactivity mechanism on cell viability. The main differences among the various glasses have been related to the modifier oxides ratio and to the MgO content, which seems to have an influence on the glass stability, both in terms of thermal properties and surface reactivity. The surface characterization and in vitro tests revealed few variations in the reactivity of the different glasses and glass-ceramics in their pristine form. On the contrary, the different surface properties before and after the pre-treatment in SBF seem to play a role on the biocompatibility of both glass and glass-ceramics, due to the different ion release and hydrophilicity of the surfaces, affecting both cell viability and protein adsorption.
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Materials Science and Chemical Engineering Department, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino, Italy. enrica.verne@polito.it
Bretcanu
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Balagna
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Bianchi
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Cannas
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Gatti
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Vitale-Brovarone
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D000327:Adsorption; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology*; D001798:Blood Proteins / Q000493:pharmacokinetics; D001826:Body Fluids; D002470:Cell Survival / Q000187:drug effects; D002516:Ceramics / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D051379:Mice; D008855:Microscopy, Electron, Scanning; D041681:NIH 3T3 Cells; D012822:Silicon Dioxide / Q000737:chemistry*; D013057:Spectrum Analysis; D013499:Surface Properties; D014961:X-Ray Diffraction; D014965:X-Rays
D001672:Biocompatible Materials; D001798:Blood Proteins; D012822:Silicon Dioxide; C023506:Glass ceramics