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Stability of Suspensions of Bioactive Particles Using Hybrid Organic–Inorganic Solutions as Dispersing Media

“…This glass presents the formation of apatitic phase films on the surface of the coatings in a simulated body fluid, as a result of the chemical reaction between the glass and the surrounding body fluid, considered as a clear sign of bioactivity [9][10][11][12].…”

“…Previous work [9] reported the preparation of coatings from suspensions of glass with average particle size of 5 µm and solid contents up to 25%, concluding that a content of particles in the suspension higher than 10 wt% led to lines of drainage in the coatings. That work focused on the in vitro evaluation of coatings concluding that a two stage sol-gel coating system that included a first SiO 2 hybrid film, acting as a barrier against corrosion, and an external bioactive layer, built up from glass particle suspension, is a good alternative to improve the properties of stainless steel 316 L.…”

“…Some authors have developed functional coatings through the sol-gel method by incorporating glass and ceramic particles [5,9]. These works remark the importance of preparing stable suspensions of particles in the precursor solution, if defect-free coatings are to be obtained.…”

Sol–gel coatings for protection and bioactivation of metals used in orthopaedic devices

“…[13][14][15] This behaviour is considered an indication of in vivo bioactivity. [16][17][18] The sol-gel method has been proposed as a suitable procedure to produce protective [19][20][21] and bioactive 22,23 coatings. The advantages and technological significance of these sol-gel coatings over those produced by other methods have been widely demonstrated.…”

“…The glass was obtained by melting the batch at 1600 uC for 2.5 hours then quenching in water at room temperature. 35,23 Bioactive glassceramic particles were obtained from this glass employing a heat treatment for 2 hours at 1050 uC to induce crystallization of hydroxyapatite and wollastonite. All the bioactive particles were milled in a planetary mill (Fritsch Pulverisette, Germany), with agate jar and balls at 1500 rpm for a maximum period of 1 h. After milling, the powders were sieved, using Tyler sieves numbers 270 (54 mm), 325 (43 mm), 400 (37 mm) and 600 (25 mm).…”