Preparation and characterization of bioactive glass nanoparticles prepared by sol–gel for biomedical applications

Abstract

Bioactive glass nanoparticles (BG-NPs), based on both ternary (SiO(2)-CaO-P(2)O(5)) and binary (SiO(2)-CaO) systems, were prepared via an optimized sol-gel method. The pH of preparation and the effect of heat treatment temperature were evaluated, as well as the effect of suppressing P in the bioactivity ability of the materials. The morphology and composition of the BG-NPs were studied using FTIR, XRD and SEM. The bioactive character of these materials was accessed in vitro by analyzing the ability for apatite formation onto the surface after being immersed in simulated body fluid (SBF). XRD, EDX and SEM were used to confirm the bioactivity of the materials. The BG-NP effect on cell metabolic activity was assessed by seeding L929 cells with their leachables, proving the non-cytotoxicity of the materials. Finally the most bioactive BG-NPs developed (ternary system prepared at pH 11.5 and treated at 700 °C) were successfully combined with chitosan in the production of biomimetic nanocomposite osteoconductive membranes that could have the potential to be used in guided tissue regeneration.

Bioglass implant-coating interactions in synthetic physiological fluids with varying degrees of biomimicry

“…The contribution of P-O bond vibrations (elicited by the orthophosphate functional groups, Q P 0 , which are typically the dominant phosphate environment in such glass compositions), 50 is hard to deduce, due to the low P content of the films and to the superimposition of the highest-intensity IR bands of phosphate with those of silicate. 40 As expected, the gradual increase in the silica content of the BG-3S and BG-5S films was reflected in an augmentation of the polymerization degree of the films' glass network.…”

Controlling particle size in the Stöber process and incorporation of calcium

“…Bioactive glass nanoparticles can also be incorporated into nanocomposites [22]. Whilst the synthesis of monodispersed Stӧber silica nanoparticles has been achieved previously in literature, the addition of calcium significantly complicates the procedure and can cause the particles to become irregular in morphology [23] or to agglomerate [24][25][26]. While nominal compositions of particles are quoted in the literature, the final compositions are rarely ratified by analytical techniques or only non-quantitative energy-dispersive X-ray spectroscopy (EDX) data is provided [3,25,27].…”

“…Several groups have attempted to incorporate calcium into silica nanoparticles by using a two-step sol-gel process in which precursors of silica and calcium (TEOS and calcium nitrate respectively) are hydrolysed in an acidic solution before gelation under alkaline conditions [24][25][26][27][28]. While EDX data showed calcium was present in the particles [25] and they induced HCA formation in simulated body fluid (SBF), little or no quantitative analysis was performed on the final elemental composition. The particles are also seen to be aggregated and irregular in both size and shape [24,25,27].…”

“…While EDX data showed calcium was present in the particles [25] and they induced HCA formation in simulated body fluid (SBF), little or no quantitative analysis was performed on the final elemental composition. The particles are also seen to be aggregated and irregular in both size and shape [24,25,27]. Labbaf et al incorporated calcium by adapting the process used by Zhao et al [29] in which Boltorn™ polymer was used as a template in the sol-gel process before being burnt out during calcination.…”

“…However, despite being spherical and dispersed, the resulting particles did not show a homogeneous size distribution even after optimisation of the polymer:TEOS ratio. Some papers have attempted to improve the dispersion or shape of the nanoparticles by use of a surfactant [25,28]. However, this can inhibit calcium diffusion, therefore limiting the amount of calcium that enters the glass [1].…”